[2023] Why do the sp for vehicles sometimes change for no reason

If you are in an up tier, the SP cost will be lower.

If you are in a downtier, the SP cost will be higher.

Originally posted by SoverignBanana: No i mean in uptier the vehicles sp will randomly change. i.e. the AH-1Z costing 588, a few rounds later, 569, without using light tanks

Depends on the amount of up tier you had.