Help with Ultimate Texas Holdem strategy

My first post but have been a Wizard follower for perhaps 20 years!

I just started learning UTH basic strategy and 21 out rule provided on this site and have been practicing with the web-based game here which will tell you when you are making the wrong move. It's my understanding that the suggestion is always correct (but obviously doesn't guarantee a win).

I've had several instances where I'm following strategy but I get the suggestion warning and I don't know what rule needs to be considered to get it right. Here are some examples after the flop where calling was apparently the correct choice:
Hole; Flop
Qh 7d; Kc 10c Jh
5h 9h; Jh Ac Ah
7c 3c; Ac 5c 4d

This is example where checking is correct:
4d 8d; 4c 9c 5c

Post Flop strategy seems pretty straightforward:
Medium Raise: Make the 2X raise with any of the following:
Two pair or better.
Hidden pair*, except pocket deuces.
Four to a flush including a hidden 10 or better to that flush

. Are there additional rules that should be added? 21 out only applies after the turn/river, right?

I've had some situations where I believe the guidance is incorrect. Just fyi.

The Wizard's basic strategy isn't perfect, that's why it is a basic strategy. The analysis page for UTH indicates that deviations between the basic strategy and perfect play cost 0.054% in element of risk terms. You can check these with the UTH strategy calculator.

For your first example, you are holding Qh7d and the flop is Kx10cJh. The basic strategy says to check but using the calculator, we see the EV of raising is 0.518012 and the EV of checking is 0.430580. You have simply noticed cases where the basic strategy deviates from perfection. In this case I think it is because the basic strategy doesn't include cases where you have both a potential high card winner and an open-ended straight draw on the flop. It is certainly possible to devise a more complex strategy which includes more cases to get closer to perfection.

Thanks! I messed around with the calculator to figure out what the breaking point is on my examples and it seems that the following simple rules should be followed post flop, numbered from my examples:
Raise:
1: Any outside straight draw with 10 or higher being lowest card.
2: ANY 4 to a flush is raise assuming suited hole cards or if one is Q or higher.
3rd example is same.

Check:
Suited flop unless pair of 5 or higher. There are some situations with raise on pair of 4s but I can't seem to figure out when. Never 3s or less.

It's been my understanding that the guidance is formed from the same source as the calculator so it should it should always be correct. Can anyone confirm this?

When ever I have put questionable guidance into the calculator, it has always agreed.

Here is the best published Ultimate Texas Hold'em Strategy that I am aware of

Discount Gambling UTH Strategy

It isn't perfect but it embraces some of the complexities that you are pondering.

Thanks! Some of these are a little complicated. Is there a rule here indicating raise with 4c Ks; Jh Js Qs? I couldn't find one post flop. Difference in EV seems marginal.

BTW, what IS considered marginal EV?