@michaelth The "Fuel Flow KG/HR" text was based on our reference aircraft, and as the text is part of the texture (as opposed to it being a text decal) it wouldn't be possible to swap that via an option on the EFB.
We can look into the possibility of having the units on the display toggle between KG and LBS via an option on the EFB, but this may be confusing if the displays are all indicating LBS and the text indicates KGs.
We've logged this on our internal bugs/feature request tracker for us to take a look into for the next update to the F28.
Mark - Just Flight