One more thingI forgot to mention that when I had my last cyst, they didnt know either if it was a real follicle or just a leftover cyst. Since they made me wait anyways, I ended up getting checked again a few days later and for sure it was a leftover because according to my BBT and P4 check, I never ovulated (I know some will say BBTs are not accurate, but I have been tracking mine a long time and for me, they are, and the trends do correspond to my actual b/w numbers and a low BBT for me has always corresponded to low P4, and vice versa).
I also had follow-up b/w and my P4 was low. I got AF on CD 12 of that cycle, so they said it really wasnt CD12, but rather I had breakthrough bleeding earlier (so my CD 12 was really CD 40-something). So, in my case it really did end up being a CL cyst. But, as AJ said, its also likely that it could be an early recruited follicle. But regardless, as the others are saying, I dont think Id trigger for IVF in such a situation, especially if you are paying out of pocket. Maybe you could trigger and do IUI or TI?