Just looking for a bit of advice from the regulars.

I'm trying to book LHR-IAH-LAS-IAH-LHR on a LON-LAS V fare. (100% earning in LH M&M). Outbound LHR-IAH-LAS is fine.

On the return I want to do LAS-IAH(23 hours)LHR. So NOT technically a stopover. I'm looking at arriving at 16:31 on day 1, and departing 15:45 day 2.

My problem is LAS-IAH is showing married segment availability. As a standalone, the best avail is E8. Married with the IAH-LHR segment it's V9, as is the IAH-LHR segment.

So my V fare should be valid from LAS-IAH-LHR, because there's no stopover, and the through availability is V9.

ua.com won't let me book it, because it's looking at the LAS-IAH segment as separate segment.

Before I go into a long discussion with a UA agent or a TA, is my understanding correct? Despite there being a 23 hour gap, this should be bookable on a V fare?