A good shot should fly up that ramp pretty easily. As others have said, it sounds like a little flipper rebuilding action is in order. Also check your pitch and level. You mentioned all of the levelers are at the same height...I'd have to look to be sure, but that's probably not right. Don't go by what the levelers look like though, go by what a level and inclometer on the playfield tells you.

If the machine is set-up correctly, you can even make that ramp from a trapped ball on the right flipper...very tough backhand shot. It doesn't have much oomph and just barely crawls around the corner of the ramp, but it will make it. You have to just BARELY clear the slingshot. Fun shot to nail.

Great game...one of the best. Good luck getting yours up to speed!