Hi Shak'n, side by side!
I've gone into RFM Section 9 - Performance and produced a table for recommended Cruise and Range so the guys can set an IAS in the air and a TAS and Fuel flow for planning. At ISA +15 it makes quite a difference, 0' 152 TAS 486 FF, 10000' 140 TAS 377 FF. On the longer legs this gives us up to a 120kg advantage over the fixed TAS/FF depending on CRZ ALT.
Table 9 in Sect 9 give a DTQ correction factor for various optional hanging off equipment, but not the Gear down situation.
It seems there is about 5-6% increase in FF or reduction in TAS (thanks guys), it would just be a bit neater to have an Agusta derived CF to apply.