I want to get a heads up on this before I go back to UAL on this.
Here's what happened....

I purchased a B fare which included 2 legs.
I upgraded with 15K miles to C.
The 1 leg cleared OK, but the other was waitlisted. At the RCC AFTER the 1st leg, I checked and C was going to be full with GS/1K, so I asked about upfaring to C, which as it happened wasn't much more. That would at least guarantee me a C seat.

Now, I also asked if the 15K miles (I used earlier) would possibly get me into F. I was told Yes!

Now, when I look, an EXTRA 15K miles have been taken, so in all I've "paid" 30K miles, when I think it should have only been 15K.

Am I right?
Surely it would be the same if I booked 1 leg on a B fare and 1 leg on a C fare and used 15K miles (that would then book me into C and F respectively right??)