Ann: Outstanding West Erregulla Flow Test Results, page-168

W4 had much larger tubing and a smaller choke, which means the pressure "push back" was concentrated at the wellhead. Large volumes of gas could come into the wellbore and up the tubing but then ran into a (literal) choke point at the choke orifice. That's why the wellhead pressure at W4 was so high.

WE2 had smaller tubing but a larger choke. Not as much gas can get up the tubing and when it gets there, the choke point is much larger so the resistance offered by the choke is much less, so the wellhead pressure is much lower.

W4 - 5.5" tubing trying to flow into a 1.5" orifice = high wellhead pressure
WE2 - 3.5" tubing trying to flow into a 2" orifice = low wellhead pressure

The difference in depth matters too. There are equations that can correct for tubing diameter, length and choke size, and I think if you did the calculation, you would find that WE2 drilled with W4 tubing and choke would have performed similarly to W4 and indeed outperformed it. The reservoir these wells are producing from are all capable of rates far in excess of what have been reported, they are just limited by mechanical constraints.