no need think until so far.
epica 8km/L vs sonata 10km/L
every shift 320km done
40L for epica vs 32L for sonata
8K different-8x1.22=almost $10 different.
imagine sonata FC is 12km/L
40L vs 27L-$16 diff!
can buy 2 sets of 
for my kids.
haha. some ppl will just brush it off....say $10 per day nia....
1 more quality pax can cover liao. but the fact is, 2 km/l diff
becomes 8900km x 2 = 17800 km diff per yr!!!
and that's more than a 13th mth bonus!!! even 14th mth bonus
liao....
half full or half empty...... if u dun earn that 17800km, u save
that.
thinkof it, quite scary also.