Natural cycle FET vs. Medicated cycle FET?

Merlynn • Currently pregnant, IVF FET 12-23-16. First baby born 2-13-16; IVF FET 5-29-15.
Hi ladies, I'm in the TWW of my second FET cycle. Both this cycle and last I'm only doing prometrium vaginal suppositories. No progesterone shots, no estrogen leading up to the transfer. I wonder if this one doesn't work out if i should try a medicated cycle next? My doctor says I don't need to but won't it increase my odds of success??