I'm beyond puzzled with huge disblief - Clark shoes fitting size

[Riverbreathes]

Just came back from Clarks, shocked and speechless. Completely lost.

Being told DS's feet size is about 7.5. I initially thought they must have meant a different measuring unit, as DS was wearing a pair of Clark-fitted shoes of size 10 - for over 2 months! The lady didn't seem to bother much in the beginning, but once DS has tried the new 8.5 shoes on, obviously they fit with slight growing space. She then admitted whoever measured him last time should never have had put him on a size 10. Then she and another lady were quite surprised when I told them we measured him in the same shop last time. They did ask some details and intended to follow up with their internal procedure (don't know exactly what that would be).

I came back home, seeing DS happily wearing his 8.5 shoes without any complaint and feeling horrible. Then I managed to find all his old shoes out. Guess what? I have 1 pair of 7.5, 1 pair of 8.5, 1 pair of 9.5 and 1 pair 10. All from Clarks!

How could this be even possible? I remember the 7.5 pair was from last winter - I mean the winter-spring of 2015! I only bought online once and for all the other times, we've always been in the same shop to measure physically just to avoid getting it wrong.

How could this be even possible? Would it by any chance their feet size shrink, e.g. they arching up and measuring less in length?

It doesn't really matter what size it says the shoe is as long as they fit. Different styles vary. You can tell yourself easily enough if they fit. I order online (not Clarks but other brands like Bobux) and try them at home where you can have a proper look at them in the shoes.

I understand it can vary a bit by style but personally I just measure DD myself, buy online and check fit. It's not that hard and then you know you can rely on it.

I understand different style may vary. But we are talking about a difference of 2 size here...
I've squeezed above his big toe to check each time, but honestly a bit clueless how tight/loose it shall be. Plus all the Clarks shoes are a bit hard on the tip size, hence not easy to gauge how tight/loose it is.

We had a complete width screw up by Clarks when dd's feet grew up a size. Cost us 30 quid in shoes that, once worn a few times, can never be worn again. Last time I trust Clarks and, to be fair, not sure I'm going to trust normally sensible dh with shoe buying again.

Does it matter though as long as the shoes fit? Do you not check with them that the shoes fit and aren't slipping off the heel? You'd have noticed if they were too big surely?

All seemed fine at tbe shop. Of course there were checks. But it went wrong after a few days' wear.