Bed leveling and mechanical z endstop

My set up is a mechanical Z endstop and an inductive bed sensor. When X and Y are homed, the inductive sensor is not above the bed, and as such homing Z will not work without a head crash unless I use the mechanical Z endstop. Once the bed levelling procedure is complete, I have to send a G92 command, or else the head is too low/too high for the first layer. This G92 command needs recalibrating every few days, so even though I know the bed levelling itself is working because the first layer is perfect after sending the G92 command, there is still this offset that drifts one way or another. The inductive sensor is connected to the Z max stop and is NC.

Is having to send this G92 command rather than using the offset that is set at compile time because of using the mechanical end stop?
If I move the sensor so it is above the bed at XY home, do I do away with the mechanical end stop and fix this inconvenient problem?

Thanks :)