30 ltr fill on 47 ltr tank!

[hsdd]

Hi,
I am new to lpg and have recently had a Romano system fitted to my 08 Subaru Forester petrol auto. Really pleased with it but can only get about 30 ltrs
into the 47 ltr tank. Fitter/Romano say its because this is the smallest of tanks and because of the amount of variables with lpg (temp,pressure on system and garage pump) this is acceptable. Given the accepted 20% freespace and that Romanos own spec sheet states that the nominal fill is 37 ltrs I wouldnt mind some advice.
Thanks in anticipation!

[ruulis]

try other fuel station. when I cross europe back home i fill it up few different stations, but only few litters different. my tank 47 for some reason i can fill up 50 litters...

[Liska]

try other fuel station. when I cross europe back home i fill it up few different stations, but only few litters different. my tank 47 for some reason i can fill up 50 litters...

I know, it's strange.