I would really reccomend if you are going to mess witht he modulator pressure to use a bar gauge and do per spec of color and type, 722.3, 722.4..etc. You could be limiting the life of the transmission. The reason for the diesel owners messing with the pressures are they really do not know what they are doing and should be going after the vacuum switches on the top of the valve cover or side of injection pump that are broken.

Just a thought from someone who has seen this a million times over.