Learn English – What’s the meaning of “What time do you call this?”

OP's context is an example of OED's definition #3 for the phrasal verb to call out (first recorded 1823)...

To challenge to fight (esp. a duel).

It's effectively a figurative extension of usages such as...

"Come outside and say that!" (repeat your insult, and we will fight where it is more convenient)

...but the modern usage doesn't directly refer to fighting with duelling swords or fists. The metaphoric "weapons" which will be used in the "contest" are justifications (facts and logical arguments).

By implication, the person issuing the challenge expects to win, because he doesn't think the other person actually has valid justification for whatever he said, implied, or did. It's important to note that you can just as easily be "called out" over disapproved-of action (or inaction) as a disputed statement...

"If your husband never helps with the housework, you should call him out about it."

That's to say, to call [someone] out over/about X means to demand that they justify X.

"Dare I say" or "dare I ask" should both be understood by your readers.

For this particular context, alternatives might be:

• "If it's no trouble, ..."
• "It would be helpful if ..."
• "Although it's not required, I would appreciate ..."

On the other hand, if you're making a deal-breaking demand, you might want to word it more forcefully.

If the application includes a spot for custom requests or ideas, that's what they expect you to put there - no apologies necessary.