Yes, its exactly like this, even the number format is "general".
What I have is user defined occupancy rates that start at 0 all the way to 100, in increments of 0.01, the range is therefore rather large but frustrating because the lookup value is always out by a small fraction.
Further to this, how can it be that if I get vlookup to look up another value and then afterwards change that value back to the one that I'm looking for, the answer comes up correctly but a further try gives the incorrect answer one again.