I never claimed this game followed basic logic in some of it's design decisions. Infact every single mechanical/system problem in this game comes down to things using the * that shouldn't I hate to say.
Beyond that though did a quick test and viewed log. Keep in mind number in () is what the damage should have been, outside is actual after resists AFAIK
Total Reduction = 57.3% (35% shield power, 18% EPtS 1, 20% DIS)
Hit: 70 (124) or reduced by 43.5%
Total Reduction = 54% (35% shield power, 18% EPtS 1, 10% Maco, 5% Resilient)
Hit: 184(354) or reduced by 48%
My conclusions from those two numbers are:
1) Shield resist does have built in diminishing returns
2) Maco 10% and/or Resilient 5% are not subject to said diminishing returns.
If we then go look at STO wiki and the armor diminishing returns we see that 100 magnatiude which would grant 50% resist without the built in penalty in the formula grants 48% instead. So what I'm seeing above is not lining up as the penalty would be too severe.
Moving on if we instead assume the log is lying in some way perhaps instead that would explain it. Even then I cannot see a way to make it work properly I will need to re-think my test methodology and try again some other time.
Interesting, well thanks for testing this at least.
I have a few testing ideas I'd like to try but my time is a bit limited at the moment unfortunately.