There is no extra anything. If you want 65% hydration, you have to use 65% water. If you use more flour because you find that the dough is too wet for your tastes, then it's not 65% hydration; it's something less than 65%. Furthermore, your measurement becomes merely a guess.
Bakers' percents are used to achieve precise measurements. If 65% is too wet for you, then deal with it for one batch of dough, then change your hydration level to 60% (or something like that) for the next batch. If you don't use precise measurements, there's no point in using bakers' percents.