Seems unlikely. What are you using for a data source?

Nothing authoritative. I don't have the POH's. But a pilot of my
acquaintance first asserted the difference to me. He claims to have
researched the issue thoroughly before he bought his -260. He claims
that bush pilots prefer the -260 for that reason.

The only supporting evidence I have found is a web site that had
performance specs on the a/c and it validated what he said.

I agree that it seems unlikely, but I'd prefer to be able to show the
guy some data. Every now and then, something unlikely turns out to be
true. ;-)