The only factors, I am avare of, is number of active engineers, during losing a base.
I remember in old WITP, I have used too small force to take Palembang, and it was forced to retreat. After some time, and reiforcements, and lots of air, and sea bombardments, I have taken base intact (not much left from Allies unit, after all those bombardments).
While for Batavia, I prepared lots of forces, marched them from nearby base, and took Batavia in one attack, without earlier bombardments - base was completely trashed.
Of course it would be harder in AE, because there is now chance, that bombardment will target industry.
Inqistor, I think as time moves on it makes less and less sense to refer to the old WITP because as time goes by the relationship gets less and less distinct. Hal
Only assuming, that this part of code was rewritten. But I am not sure any part of ground combat was touched (except monsoon effect).