It does because it is harder for the body to digest formula so it stays in the belly longer. Good or bad, that's the fact of it.
I bfed my babies and my youngest didn't want solid food until close to 8.5 months. Even then -- well, my kids were both terrible sleepers. Many Bfing moms have sleep issues for a year or in my case, more, but for me it was worth it. At least in hindsight it was. :)
I congratulate you on making it this long and I empathise with the lack of sleep. If you're supplementing at this point, I don't think it's bad but I wonder if it's hunger or habit and wanting mommy more at this point.
IMHO, getting up, turning on lights, finding bottle parts, mixing, heating, testing, all of that is so much more work in the night than putting him next to you, and lifting your shirt while you drift back to sleep.
Whatever you decide, I hope you get more sleep because of it!