The tension of a string is a function of mass^2 X scale length ^ X pitch, divided by a constant. Yes, increasing the scale length by moving the string up to the next notch of the slightly longer scale will make a difference. BUT...if a B-G string set is optimized for the fanned fret scales, from experience of designing my own fanned fret bass, see this thread:
A Different Custom P-style Bass , the @ 1/2 to 5/8 inch difference in scale string-to-string should not make an appreciable difference in tension, and may even help the stability as each string is positioned up to the next longer position on the neck; maybe if necessary a slight tweak to the truss rod.