Martin, per my experience with F&P ...
GWL11 has 24v DC power on the valves. ATC directly mixes the hot and cold flow to the target temperatures. My IWL12, which is a Phase 6 model same as GWL11, targets 115°F for Warm, assuming the hot supply is at least 115°F. Hot supply of 140°F, the water spraying in remains at 115°F, assuming the cold supply isn't also 115°F or otherwise too high to moderate the hot down. GWL11 and IWL12 have different target temps programmed on the board.
Phase 7 (and higher?) apparently went away from digital control. My AquaSmart runs in full hot (or cold for the two lower temps) until the ATC thermistor goes too high above (or below) the target, then switches to mixed hot+cold to cool (or raise) it for an average target in the tub.
All F&P models will throw a hot or cold supply fault code if unable to reach the target temperature (non-fatal, meaning filling continues with angry beeping). It may take a few mins for the fault to trigger so Eco Active fill or even Low level may be reached without a fault occurring.
These are the target temps for my IWL12 and AquaSmart per diagnostics:
Controlled Cold = 16°C/61°F \ 18°C/64°F
Warm/Cold = 34°C/93°F \ 30°C/86°F
Warm = 46°C/115°F \ 50°C/122°F
Warm/Hot = 51°C/124°F \ 56°C/133°F
Hot = 69°C/156°F \ 62°C/144°F
IWL12 has a set-up menu option to adjust the target temps (all together, not individually) on a range of +6°C to -6°C in 2°C increments. GWL11 does not provide that option (nor does AquaSmart).