Starting load question?

[Mr. 16 gauge]

I'd like to play with some heavier loads than I normally shoot in my 6.5x55 Swede, so I plan on ordering some 140 grain Nosler and I also found some Norma 156 grain bullets I'd like to try.

Problem is, I don't have any data specifically for a 156 grain bullet.

I do, however, have some loads for 150 grain and 160 grain bullets, for various powders.

Does it seem logical and responsible to start in the middle of starting loads for those to bullet weights, i.e if a 150 grn starting load is 40.0 grains of powder X, and a 160 grain starting load is 30 grains of powder X, would it be reasonable to start with 35.0 grains for the 156 grain bullet?

It seems logical and reasonable to me, but then again my wife tells me that my brain doesn't work like a 'normal' persons.