Are you remembering to add in your pressure to the head chart? 50 psi = 115 ft of head + the 100' of static once the well draws down. You need to be looking at the 200 ft of head line, not the 100 ft line.
The 7 GPM pump is more expensive because it has more stages. You have a little bit of a tricky situation because your well is going to draw down once you start using water. The 10 GPM pump will give you better performance at first but will drop off once the well draws down to 100'. The 7 gpm won't quite give you as much at first but as the well draws it will beat the other pump.
I might go with the 10 GS because at some point you're going to run out of water in the well. Having a pump that won't beat the well output would be a plus in this situation. The 7 GPM will outpump the well eventually and you could damage the pump.
If I were you I would also look at a system to detect if the pump goes dry to kick it out to protect it.