Carlos, I expect that 90 degrees should put the final torque value very close to the 68.6 Newton meters attained in Step2.
Consider that the head gasket has already been "squashed out" significantly in the earlier Steps 1 & 2 and that means that very little (if any) additional flattening and spreading of the gasket will occur in the re-tighten process.
Usually if the bolts are deemed as "Torque To Yield" type fasteners the OEM mandates new bolts be used in head and/or gasket replacement.
I do not see Nissan making bold statements in the manual to use new bolts every time.
My position on that is to replace bolts that show any pitting or rust/corrosion or other obvious defects but reuse them if they pass inspection.
Bolts labeled as Torque To Yield get replaced without even considering them for reuse.
By the way, Steps 3, 4, & 5 are actually supposed to be done AFTER running the engine to operating temperature and then allowing it to cool. But we don't and I actually think very few people bother to do that.