Sending ACT vs SAT Scores

I have a few questions regarding sending ACT/SAT scores to colleges:

First off, I have taken both the SAT and the ACT. When colleges say they require all ACT/SAT scores (no score choice allowed), does this mean I must send all scores from both tests, or can I pick either the SAT or ACT and send all my scores for that one test? Basically, is there any way for colleges to know that you have taken both tests/require all scores from both to be reported.

To go along with this, I should share my own situation. I scored a 34 composite on my first and only time taking the ACT and a 1560 on my second time taking the SAT. Both scores are very close to one another, but most conversions tell me that my SAT is equal to a 35 ACT, showing that it is slightly “better” than my 34 ACT. So my question is, should I only send my SAT scores and pretend as if my ACT never happened? (By this I just mean avoid sending my ACT scores to any colleges) I also realize my ACT/SAT scores are very close to one another, so is there any benefit in sending both just to show colleges I could do well on both tests? Or would this only hurt me/have no effect at all?

Thanks!

might as well just send both

I would send both. They are both excellent. Some colleges require all scores from all tests, Yale being one, so you have no choice.

If the school asks for all score, send both. You have nothing to hide. In addition, even a 34 in ACT composite may have a good section score that may help your SAT 1560, for instance, if you have 36 in Math section of ACT but 760 in SAT. Note that the ACT and SAT scores are not directly convertible. Each school would look at different section scores with different weight. When you look at the mid 50 for ACT and SAT of each school and you will find they do not always match for that reason. If budget allows, send both scores and let the adcom pick the best one for you.