Base timing

Hey guys, I'm a beginner at ECU tuning, and always looking to learn. Now I brought a car with aftermarket ecu, its tuned etc, isnt perfect so will be going back to a dyno, but I noticed that the base timing must not be paired between ecu and engine, as when locked the ecu says 10 degrees but engine is reading I forget now but it was much more. My question is more out of curiosity then anything, if the two were paired now, would the ignition map need to be returned to adjust for the change? The answer is probably really simple and obvious but I think I'm over thinking lol cheers if anyone can help

Remember if its wasted spark, it will read double the timing on the engine than what the ECU shows.

wasted spark meaning for example 3 coils on 6 cylinder, it sparks each cylinder every revolution instead of every second as it’s usually needed

its a 1jz, individual coils , microtech lt16c. Let's simplify this. If I you were to lock the ecu at 10 degrees and then engine was reading so 20 to keep it simple, and then I adjusted to match at 10, is the ignition map then useless or will it perform the same as before?

The whole thing will be retarded 10 degrees unless you offset the map by the same amount in the opposite direction. It is generally safer to have correct ecu/physical timing so a tuner doesn't just load something up and give it some (best practice is to always check but it doesn't always work that way) that but note that often micros were intentionally reference retarded on rotaries as they couldn't handle negative timing values in the maps. So if you have some really low numbers it may be offset for that purpose, i haven't really bothered following micro software/firmware development though as i wouldn't ever buy one so that may have changed.

Also if it is correctly set up waste spark either 360 or 720 degree real trigger cycles(noting you could nominate a missing tooth/360 reset as actually being a 720 cycle and run "waste spark" that way but you are asking for fuckups doing that) the light will still be in the same spot, but you will also get the opposite side of the pulley with no mark, it won't phase shift unless you had a really weird setup like a ~15 degree v6 running wasted which i don't imagine anyone would probably do, or the dodgy as hell 720/360 fudge which I wouldn't recommend.

Yeah I was told its better to have the two synced for ease of diagnosis and less confusion, as what I had, when I checked it I was like wonder if it was never done, is there an issue etc