Which board? My P8Z68-V LE is the same way (I can only use offsets).
Now, every chip is different, obviously, but I can do 4.5 on my 2500K with just a +.020 offset (which gives me 1.328V). I OC with the main multi and not the Turbo multi's though.
My temps in Prime with my 212 Evo are in the low 60's, but the load voltage drops to 1.277V because I don't have LLC enabled, but it's still completely stable.
1.4V is WAY to high for 4.5. You SHOULD be able to do 4.5 at around 1.330V or less, although I've seen a few that need a bit more (one I saw just recently actually DID need 1.41 to be stable at 4.5, but I consider that an outlier).
I actually don't have "levels" either. It's either Enabled/Disabled/Auto for me, but Auto doesn't seem to do anything because it acts the same as Disabled, for me. And Enabled just cause the voltage to be WAY higher than it needs to be, so I just leave it disabled.
Seriously though, try a much lower offset, like +.025 to see how that goes.