Vertical Wall flange is low

[jfpt89a]

remodling the bathroom, trying to get the rusted bolts out of the old toilet tank and broke the bowl. Of course! Researching new rear outlet toilets (Very expensive). I found a Gerber 21-310 at a reasonable price. Gerber says rough in is 4 1/4" My current flange has a center line of approx 3 1/2" and I really have no easy room for any adjustments.

My question: Is there any wiggle room in the meeting of the flange to the toilet, my set up is approx 3/4" low on the wall.

Thanks