I also have the Deka 630, and I also have a not-steady idle when warm, and a pig rich idle when cold.
From a topic jsmcortina created
Megasquirt-3 MS3 Injector Dead Time Measurement :http://www.msextra.com/doc/ms3/injdeadtime.html
the Deka 630s will have a 0.4ms deadtime @13.2
That is what I use. But when idling, it will show a 1.2, 1.3ms PW, which is the non-linear region.