As one of those pesky YYZer's always cluttering up BUF thought I would take the opportunity to try to help out a Buffalonian.

I suspect that this should have been posted in the Mileage Run Discussion forum, where the stickies provide more than you ever wanted to know about MRs.

I think your calculations are for RDMs when I imagine your main interest is EQMs.

A quick ITA search for May (3-4 day duration) shows some dates for $240ish BUF-IAD-LAX-LAS-LAX-IAD-BUF on all UA metal which nets out to 13120 with DEQM (according to webflyer mileage calculator).

If not already familiar, OP should follow the ITA Route Language link in the MR sticky ('specially in these DEQM times, O:: is your friend to find United operated flights).

Hope this helps.