Technically, I can't see what all the fuss is about - both ways have an adequate safety margin and little to no effect on performance.
However, I can see why some trainers might get concerned by a movement away from SOPs in their presence, especially in the "add a bit for Mum" department. They're probably wondering if there's a random increment to approach speed, engine failures are flown at V2+35 and 2T of extra fuel loaded when they're not around. Adding things on all the time "to make it safer" can get quite compulsive - and it often works in the opposite sense to that intended. Not implying that the OP does any of these, of course.
I'd hazard a guess that this is more a HF issue than a technical one, especially if CK occupies the LHS...