[Mobhack]

Wait till the end of the purchasing, then buy the battery that consists of 2 sections/platoons and the second unit will not be purchased, but the first will be if sufficient points are in the bank.

Same as buying a tank platoon of say 5 when insufficient points available for all 5, you will get 4 or less.

Then use any remaining points for bits and bobs and continue to the battle.