This is not a "WTF" warranted thread. Although I am very suspicious as to the basis of the makeup of this "scenario" (see Chickenboy's post #16) and therefore the possible ramifications of equipment specifications, nor have we been provided with any meaningful data of what occurred at Loyang and therefore a comparison between the two locations is not possible and of no value to the OP, still there is enough provided to set the OP on the correct thinking path.
Before proceeding with the commentary there are a couple of things the OP should do himself.
(a) Do not rely just on reading the Combat Report. You must also view the combat animation to gain a fuller understanding of what factors are at play.
(b) Forget about this expectation that Loyang results can automatically be generated at Chungking. There are many significant differences between the two and the OP has yet to realise what those differences are, even though the differences are not hidden from a player.
Also before commentating on this particular incident, I strongly urge the OP to read this recent thread.
1. No timeline has been provided. Nonetheless it is quite likely that Chungking has level 6 forts whereas Loyang probably had only level 1, perhaps level 2, forts. That is a huge difference and alone would suffice to explain the alleged differences in bombing results. But wait, there are other factors too at play.
2. The Chinese have very limited flak assets.
(a) Most infantry divisions have no organic flak, and the few that do have some are only equipped with flak limited to a ceiling of less than 4000 feet.
(b) Chinese Base Forces have a TOE which includes some limited medium AA guns which can fire up to 7500-9800 feet, and a few large AA guns which can reach 27k-28k feet. I said TOE, because in reality the large flak guns are not distributed to all the units in the field and with the supply problems in china, it is difficult to fill up depleted units.
(c) The only Chinese units equipped with a reasonable number of AA guns are the two Anti-Aircraft Regiments located at Chungking. These units have flak which can reach Japanese bombers flying up to 27k feet.
3. If you read the thread I hyperlinked above, you will see the importance and effect of degrading enemy bombing. Loyang almost certainly had no flak which could reach Japanese bombers flying at 6000 feet. Chungking instead has probably about 20 guns which can fire above 27k feet and even more guns which can hit planes flying in the delta 6-9k feet. Your Chungking Combat Report ("CR") shows about 5.7% of the attacking bombers were damaged by "flak" (you have not updated the game because flak losses are now recorded separately on CRs). For the China Theatre, that is a significant loss rate and impact on bomber degradation.
4. Having flak present is in itself of no value if there is insufficient supply. You place emphasis on having destroyed facilities and blockade at your bombing targets. Loyang has very limited supply generating capacity and would have only a 20 auto supply capacity which means that even if there was any flak present there, it would not have fired due to lack of shells. Chungking is quite different. Not only is it the Ruhr of Chinese industry, particularly when compared to Loyang, even with all its industrial facilities shut down it would still generate 400 supply automatically. That means that unless the entire Chinese army is trapped at Chungking, there should still be some supply available to provide shells for the AA guns.
5. In military terms it is almost always true that dissipation of effort is not only inefficient, but prone to generate poor results. You cannot complain about your bombing results regarding number of enemy casualties (which is the wrong metric anyway, see point 6 below) when you have assigned 30% of your bombers to "city attack". I very much suspect that at Loyang you had the bombers 100% on "ground attack"; certainly after the very limited industrial facilities there had been quickly destroyed.
6. Time after time I see players assessing their performance on the basis of enemy men "casualties". It was a poor metric in Vietnam; it is fairly meaningless in AE. It is the number of devices killed outright or disabled which counts (again look at the thread provided above). All that the casualty men number records is the combat load factor associated with the various devices which have been destroyed/disabled. It is not practically possible from that metric, to ascertain which devices are involved. Nor are all "similar" devices equal in their combat load factor. But the real reason why it is such a poor metric is that the main value of bombers on "ground attack" is not recorded on the CR at all. Disruption to combat defending units is extremely important, as is destruction of supply (but the latter is more efficiently handled by "airfield attack"), and that is all handled "under the hood".
7. In point (1) above I mentioned the great disparity between the two locations in terms of their fortification levels. Just as important, because it also accentuates the protection from bombing, is the great disparity of terrain. Loyang is clear terrain, Chungking is Light Urban. Look up the table on page 189 of the manual to see the impact of the different terrain. When combined with its fortification level, even without taking into account any bomber degradation suffered, you should expect that Chungking will suffer only about 25% of the "casualties" that a similar sized and weighted attack would inflict at Loyang.
8. Bearing in mind the preceding points, on what authority do you base the statement that inflicting "250/350 kills a day is simply not quick enough" (post #7). Firstly, what is the relevance of the time; do you have to rush to the supermarket before closing time to buy a litre of milk? Secondly, as I pointed out in the above thread, "ground attack" is the wrong tactic unless you are concurrently making infantry attacks. Consistent with the lack of relevant data provided, I very much doubt that you are launching infantry attacks. Furthermore, again on what authority do you believe that inflicting 1k daily losses will ensure an easy continental win. This is not Kosovo 1999. Airpower alone does not win battles, you need the army. Have a proper army attacking Chungking and you will get far better results than is possible with Japanese airpower.