My car received it's ecutek tune via (hub) dyno. I watched the complete tuning process, and spoke at length with the (highly experienced) tuner. This tuner does a GRY every 2 weeks.
My car is a fairly standard example, yet it took around 8-10 (I wasn't counting) dyno runs to settle on a good tune. There are obviously many variables to take into account (temp, fuel, mods etc) to determine an adequate tune. 'Adequate' being still protective of engine internals and longevity.
These are just my musings, since this thread is filled with questions regarding the number of times ecutek maps have been sent for bluetooth upload via the OBD dongle.
There is no single perfect generic map, which is why numerous iterations are often required.