Too many assumptions in that question. I would note that I too have used synthetics of one type or another for almost 30 years, and never noticed consumption to be a problem.
That said, if you happen to have an exceedingly worn engine, that's guzzling whatever its fed, AND you switch from a dino with a low Noack test result, to a syn with a higher Noack percentage, then perhaps you might see your engine use more synthetic. Possibly, just going from a higher viscosity dino to a lower vis syn might cause the same effect.
But generally, all things being equal, engines do NOT use more syn than dino.