Lancake

I have a problem with my vista engines. My ship has 2 of them in perfect symmetry but one of them has a lower max thrust than the other. At 100% I get 1100 Kn with the first engine but the other one gives me only 1009.4 Kn. Specific impulse is the same for both of them but fuel flow and thrust doesn't scale correctly for some reason. With the thrust limiter i can get them around the same thrust but it is rather annoying. What am I doing wrong? I have enough power to run them and both engines have a separate liquid fuel tank.

Great mod you've got there, just the thing i needed to complete my ship. I noticed a weird thing though. In pictures i see people placing struts on each other at the sides but i can't do that. I can only put them beneath each other -> I only have 1 green dot so placing them at the side is a no-go. Is this a bug or am I missing something?