Hi,
dwell for BMW 12131748017 COPs are:
V 8 10 12 13.2 14 16
--------------------------------------
ms 7.4 4.8 3.4 3.0 2.7 2.3
they are "first generation" COPs with external IGBTs
similar design to the VAG version #058905101
3.0ms@13.2V with MAP scale = 1 is a good value,
even 3.3ms shouldn't bother them.
Check for proper wiring and tight connectors (terminal sockets),
they tend to get loose, causing early failure.
If you take used ones, check for cracks, to much heat left these marks
and better sort them out.
regards