Nope, would not agree with this under any circumstance. What you just proposed is lying to the coach. It also puts your partner a precarious light. If the coach honestly believes you missed part of the play, you have just thrown your partner under the bus just to make yourself look amicable.
If an umpire believes it is possible s/he may have missed part of the play, there should be no question about going for help if asked. An umpire should ask the partner a specific question as it pertains to the coach's concern. If you ask a question, expect a direct and honest answer. If you have no doubts you had the entire play, just tell the coach you had the play and move on.
Oh, BTW, this isn't not an appeal, just simply asking an umpire request assistence from his/her partner.
I'll get the terminology right as I spend more time involved - somehow I keep getting deeper and deeper into coaching and being involved in softball. One day I am sure I will end up umpiring probably when my DD moves onto college.
I'll clarify what i wrote a little bit because I probably wrote it wrong and there seems to be a thousand different scenarios. I am not talking about plays that shouldn't be questioned in any way (such as bang/bang plays at first with the umpire in perfect position (beyond "Are you sure? Ok" if that) - I am talking the more complex question with lots of things going on or one where there could be a better angle from another umpire (or the coach feels there could be).
I don't see it as lying - if you go to the other umpire and say "I am 100% certain I got this right, this is what I saw, did you see anything different' and they say "No" or "it is your call" or "I didn't have good view" how did that hurt exactly? I see way too often when an umpire does get one wrong but absolutely refuses to ask for assistance that the situation escalates.
As an umpire (again different sport - not softball) who had many games televised it was massively painful when I saw calls that I thought I had 100% right shown to be incorrect (often in slow motion, from 3 different angles and generally with commentary in some D1 games or worse shown on an overhead screen which I wasn't allowed to look at). When I was younger I didn't ask for help from my fellow officials as often as I should have - my ego got in the way of what needed to be done which was to use all the available options on trying to ensure we got the call right (even when we still got it wrong).