Scott,

That wasn't the "the old GFCI outlets", that was the old appliances causing the problem.

Those "old appliances" were allowed much higher ground fault current within themselves, and "those old appliances" (typically motorized appliances) would trip the GFCI protection (even new GFCI protection) simply because they were allowed to be manufactured 'that bad'. They no longer are, and thus should not be a problem.

That said, an "old appliance" which trips a GFCI is simply saying (for an "old" appliance) *I'm not real safe to use, even though I may be, or may not be, within my old limits ... like all things, progress has determined that my level of ground fault current is no longer 'safe enough' and is thus no longer allowed to be 'made in' to the appliance*.

Don't blame the old GFCI, they have always been set to trip at 5 ma plus or minus 1 ma. Blame those old appliances, which, by the way, are still around. How many homes still have 20-30 year old appliances? Quite a few.