Down grading 625's guns from 25mm to 14.5mm is interesting, actually logical for a country with small budget and no industrial capability to make their own munition.
But China has the largest industrial base in the World... They can make a lot of IFV mounted with 14.5mm guns, and in fact they did that. And 625 is just another level up.
It is strange that China have to downgrade 625 in order to save 25mm munition in their stock. If they wanted, they could built up the munition stock at what ever large amount as they wish.
A famous Chinese saying from ancient China is 兵马未动,粮草先行. Logistic support is essential before an army begins fighting. Abundant of munition and other war material must be ensure adequate before you move.