Do you have the old values and new one, my understanding is that the M20 actually comes later.
As requested:
Old cost was
200/50
340/20
total
540/70
-15 starting fuel
540/55
Current cost is
200/35
50/20
240/20
total
490/75
-20 starting fuel
490/55
The fuel is the same but the manpower is less, in addition this build give you now 2 units with access to bazookas (Lt, crew) and the M20 received a number of buffs (so did the LT).
M20
The M20 has received some adjustments to increase its ability to scale into the mid game and be easier to replace if lost.
-Manpower cost from 340 to 240
-M20 accuracy from 0.75/0.475/0.2 to 0.55/0.45/0.25
-Weapon accuracy increases with veterancy: +10%/+15%/+15%
-Veterancy requirements lowered from 880/1760/3520 to 500/1000/2000
-Veterancy 3 reduces mine deployment time from 12 to 7 seconds.
-Veterancy 3 increases stealth detection radius by 10; goes up to 35.
In other word the M20 is cheaper in manpower and more powerful.