The loads on the F50's are good, however you have to remember that Xr's F50's are 46/48 seat config. Maybe two flights a day to GEL are full, the rest have half loads or less. The communities at the moment even though they tend to winge and bitch, they do like the frequency of the services(7 a day to GEL). If a larger jet was to operate, then the frequency would reduce.
The big question is,
What load factor does Virgin require to make these routes worth while?
Xr's Fokkers do not require large load factor's to make a profit, also keep in mind it's only a 200nm sector.
JarJar