I tried it, but it is very difficult to have 25 supply level in Africa, so no possible to regenerate, I don't know, but maybe you should decrease a little the limit, or have multiple supply level options (ie : above 25 = 100% reinforcement, 25-20 = 75%, etc.). Just an idea...
I'm using it, but I gave units in the 20-25 range of supply the possibility to reinforce up to 20% of their strength.
I think the behaviour for North Africa units is historically correct; to reinforce you'll have to organize convoys and raise the supply level of some city (bengazi?) into the 20-30 level.
Surplus Consuls Dispatcher