It's not that it wouldn't count. Various assessing bodies can and do deduct a number of years' experience as 'qualifying' time. This is independent of whether or not someone 'qualifies' to perform a role, in the sense we might use the word in day to day parlance. I have seen a few cases where people have put down x number of years' relevant experience on a visa application and it has been rejected because they should have noted certain periods as irrelevant (because they were still qualifying for the skills met date from the assessing body).
What you initially believe to be 10 years' relevant experience could be whittled down, for example, to 4, depending on qualifications, role, and rules of the assessing body.