Make sure the mast bends to suit the luff round in the mainsail you are using.
If you use a Tuning Grid, you have the same mast and sails and are using the same calibration methodology as stipulated in the Tuning Grid, you should find the mast bends in a manner that suits the mainsail. Someone else has done a lot of the hard work for you. However every boat layout, mast and sail can be slightly different so it is worthwhile checking the Prebend in your boat is correct for the mainsail used.
If you don’t have exactly the same equipment as that used to develop one of the standard Tuning Grids you definitely need to make sure your mast is bending to suit the luff round cut into the sail you are using.