I believe handles can be quite difficult to apply.
I asked Allistair Malcolm to make a claret jug for me, we designed the shape together and he made it - but the first time he tried to get the handle on - which has to be done after the body has been made, it went all wonky and took itself off into two loops rather than one.
Allistair is by no means an inexperienced maker, he can do things with glass nobody has even thought of doing before.
He had to make another jug for me, to get the handle right. I believe the one that went wrong is on display in Broadfield House.
So I would think it might just be a matter of how the glass happened to be functioning on the day, with that maker, whether or not a handle would be applied in any uniform or consistent manner. It's not as if jugs were any sort of main production at Monart - they might just be inexperienced at the complexities of handle formation.
It would be too much to expect angles to be the same or, placings of the top and bottom parts either.