supercharging, and c-4 vacumn modulators, problem w/ upshifts

[LXHATCH]

having a problem since supercharger install:

My c-4 set up w/ manual/ automatic,
seems to upshift at aprox 1000 rpms higher or so in drive thru the gears, since a supercharger install.

Before the supercharger install, the trans shifted at 56-5800 in drive
now, with a roots blower,
it seems as the boost pressure on the modulator is causing higher than normal upshifts, would like to be able to get the upshifts back to around 5600-5800, as now i
will be hitting the rev limit set at 6000
on my msd
anyone had a similar experience ?
THANKS, LX