You actually have full control in ‘Program/Program Shift’…why, because you have EV compensation (or should have). P mode is great for togs that ‘run & gun’, a great many photo-journalist use P, virtually the only time I am in manual mode is when I am mixing flash and ambient light on location or flash in the studio whenI have a target aperture and light my subjects to that aperture. For this I also use a light meter which is capable of measuring flash & ambient in both incident and reflected modes. So, in ‘manual’ mode I might drop the ambient 2 stops (shutter speed) and then light my subject at whatever my target aperture is, this allows me to ‘lift’ my subject off the BG. I also implicitly ‘trust’ my ‘Gossen Luna Pro F’ light meter, it has never ever failed me, but then my background is film, when we couldn’t just chimp-away at a histogram and see where our exposure was
The OP is spot-on with his assessment of ‘P’ mode ;-)….and obviously knows a thing or two about lighting ratios 😉
