Research IV prerequisites are unnecessarily convoluted

- Problem:
You can skip Data Center to go toward Research IV and beyond, but without the maintenance parts you cannot utilize them, as you cannot trade for maintenance parts, you are trapped until you make Electronics III manually to unlock Data Center. After upgrading to Research Lab IV I realized I could not research anything anymore until I downgraded it back down to Lab III, because of the need for Maintenance III. Despite having a surplus of Electronics III from trade/loot on world map I couldn't unlock it. This is a strange sequence.
- Simple Solution:
The unlocking of Research IV should stem off Data Center to prevent this mistake and make it more clear that you need to advance to gold mining and microprocessors before going further. Sure, you can outsource everything needed, but you still have to make the Electronics III at home.
-Alternate Solution (preferred):
Remove the requirement of manufacturing 20 Electronics III to unlock Maintenance Depot III, allowing trade.

I think there is already appropriate change in the experimental branch.