We propose to perform accurate measurements of the quantum gravitational effect on OffSpec. This proposal is a continuation of the proposal from 2011 (RB 1120061) and the lost beam time session from 3/20/2012 (RB 1120062). These two session were relatively successful and resulted in a draft paper. However to come to clear and conclusion we need slightly higher accuracy. There are unsolved systematic deviations in our fitted data in the order of 1% when 0.2% seems to be possible. For this we need to perform a much better wavelength calibration than to exclude the wavelength sensitivity that will be the limiting factor. In combination with the better defined wavelength (shift) we need to repeat a set of the most important spin-echo measurements to match this wavelength because we cannot be sure that the wavelength is still the same as previous session.