Shower waste hole slope: defect or ok?

[EngineerTom]

I have a 40 mm resin tray to install (sand/cement over suspended ground floor) and a decent McAlpine 90 mm waste. The hole in the tray is apparently on the built-in fall by accident or design, so that, with the ground-flat base, the edges of the hole vary from about 4 mm to about 8 mm on either side. This seems pretty bad to me. Should I be sending this back or will the thick rubber washer on the trap cope with the uneven pressure? Anyone have any experience with this issue?

 

[cjg]

if it was me, send it back.