In principle, little lower "standing current" and anode/screen grid dissipation then maximum means longer life of the tube, especially in guitar amps and fixed bias. But, many classic amps used EL84 that way (Pa max), VOX for example. Personally, if output tubes life isn`t too short I wouldn`t mess with PCB modifications. Russian EL84 is solid sounding and relatively cheap. Another modification can be enlarging of screen-grids resistors R24,25 to the 1kOhms value, especially if the amp is frequently overdriven.