The cost went up a bit to facilitate better backteching to medics. In practise however Faust/upgrade timing shouldn't be affected or may be even better because now you get to build the tech in multiple cheaper stages so you can get them online faster.
You don't have to wait for all 25 fuel to start converting the HQ, you can now start converting it at 10 fuel and have it set itself up while accumulating the additional 20 fuel for the upgrade, likely resulting in an equal or even faster timing for the complete upgrade (unless you have very bad map control for the additional 5 fuel) compared to before. Though I haven't tested/timed this.
The HMG unlock is bugged, it's supposed to unlock at the basic BGHQ so 15 fuel faster than before. Will be fixed.
Are sure about the timing? Because you need to stop unit production to produce the Truck earlier...