Pug,
I've gone on to drive my 2.7L truck nearly everyday since my last post way earlier this year on this topic, (over 13,000 miles), lots of City, some highway, and tons of towing with about a 6000-lbs trailer weight... and never figured out or fixed the massive "off-idle" Tip-in spark reduction that these have stock.
I've extensively raised and played with MBT and borderline spark tables, and even extensively adjusted the tables and settings labeled as "tip-in" spark and etc. The tip in retard I'm referring too and experiencing is right off idle in neutral or "D", and only happens with a very sharp pedal snap off-idle, its not there once your already under load, or if you simply don't snap the pedal down,, even just pressing quickly (not snapping it) the pedal wont show it, or less of it.
I've not experimented with enabling other Mapped points as I didn't want to risk upsetting the way this truck drives over all. Just uncharted territory for me i guess.
I really cant complain with it over all though, my tune on these makes about 17-18psi boost and has Zero issues under any driving conditions I've subjected it too. I've extensively modified the shift schedule so it feels much lighter on its feet under light to medium loads while accelerating and to getting up to speed. Works great on 87 or 93 octane as I just let the Knock stuff handle it accordingly.
I gave up on the big off idle tip-in spark retard as I've decided that HP simply hasn't found it for us. And also the lack of full boost and power only in pretty much 1st gear,, again; I'm convinced its not opened up with the HP stuff.
I've opened and looked at the 2.7L stuff in SCT and they have a lot more unlocked or opened up so-to-speak,, some of it may be useless or not even enabled on this truck, but I'm convinced that lots of it is, and may fix what we're after. There is one specific setting in SCT that I've mentioned here a few months ago that is a power limiter that has a setting of "13mph". I believe this is the one that is holding us back in the 2.7L ecoboost trucks while in first gear from a dead stop. I've played with many other things in HP and its just not there.
As you experienced: my truck is the same way -- if you get it rolling and then nail it just past about 11-15mph,,, it has full power in 1st gear,, it very noticeable seat of the pants and can 100% be seen in the data logging too.
I've also asked HP to enable us the minimum over all commanded spark too. They have it in the 2015+ 5.0L tuning, but not in much else has this setting opened up, including the 2.7L trucks. This setting can help a ton once you get used to it and what you can get a way with providing that it doesn't "cap" trans TQ reduction from happening, some idle stuff, and Cat-warm up too. I usually set this one to anywhere from 0 to not much under -3 and found that this fixes a lot of tip-in and other timing issues, (primarily tip-in stuff) when you cant find it anywhere else. My truck goes -15* to -17* when this occurs off idle, most drivers and consumers don't notice it or don't care.
Thanks