Your sentence doesn't quite make sense ... but then I noticed your car model ... you are referring to the reading on the FC meter? If yes, that is not an accurate way to determine your FC ... you can use the moving bar as a guide for whether you're using more or less petrol depending on how hard you're stepping on the accelerator, but that's about it. Sounds to me like you did a lot of highway driving ... but don't worry it's normal, if a GE Fit/Jazz pump full tank and straight away hits the highway the FC meter will always show 18-19 till low-20s km/L readings.
If you want accurate FC, reset your trip meter to 0 when you pump full tank ... if you really want to try to be consistent, pump till the brim. Drive till you need to pump again, then repeat the reset trip meter / pump till the brim again. Your real FC is your distance travelled on your trip meter divided by how much petrol you pumped ... monitor this over 3-4 pumpings, and average them to get your cumulative FC.
P.S. you make it sound like pumping your tyres to 220kpa is an increase ... what were you pumping it to before?

FYG standard passenger car tyres (keyword: Standard) load ratings are tested based on tyres at 35psi which is ~240kpa. It probably doesn't affect average folks, but when you pump lower than 240kpa you compromise on the max load your tyres can support.