Something seems a bit odd on that tune... but it might just be that rifle and what it ended up liking.
The hammer spring tension is nearly maxed out, which doesn't seem right given the 59.5 fpe muzzle energy of the 31gr slugs @ 930 fps, especially with the 700mm barrel. 150 bar regulator pressure is going to require more HST to open the valve, but your current HST seems awfully high given the 59.5fpe muzzle energy.
Did they install the slug power kit (specifically, the 2x hammer spring spacers/weights) in your rifle? If they didn't, adding the 2x hammer spring spacers will add a little weight to the hammer for slightly more dwell time as well as increasing preload on the hammer spring so you can achieve the same hammer spring tension at a lower macro & micro setting so you don't need to run the hammer adjustment nearly maxed out.
If they did install the slug power kit, you may want to see if they adjusted the C1 protrusion to the correct distance. Also, when it comes to the slug power kit you really only need the 2x hammer spring spacers in the M3. If you use the rubber ball inside the valve return spring in the M3 it limits valve travel and severely restricts maximum power. Also, many have reported reduced velocity and power potential if using the valve return spring included in the slug power kit in the M3. You may want to try the current regulator and hammer spring settings with both the stock M3 valve return spring and the slug power kit valve return spring at the same valve settings and see what happens.
Also, I'd recommend increasing the first regulator pressure slightly to about 20-25 bar over the second regulator pressure, the current 10 bar delta might lead to some second regulator inconsistency as well as a slow plenum refill time.
For reference, I'm shooting the .22 NSA 27.5's in my 700mm M3. My M3 has the 2x slug power kit hammer spring spacers installed, a huma high flow pellet probe, and an Ernest Rowe dual transfer port (slightly larger than the stock M3 dual transfer port.)
My tune is 160 bar 1st reg, 135 bar 2nd reg, 1.5 turns past 4th line on valve (full open), 16 macro, 2.75 micro. This gives 955fps / 55.7 fpe with the 27.5gr slugs (your 31gr slugs at 930 fps are a bit higher at 59.5 fpe.) Peak velocity at those reg settings with max hammer spring tension is 985 fps with the Huma pellet probe (59.2 fpe.) Peak velocity was about 1005fps (61.7 fpe) with a Nielsen pin probe which flowed more air than the Huma pellet probe, but the pin probe didn't play nice with pellets so I went back to the Huma high flow pellet probe-- being slightly more restrictive it gave up a little peak velocity with the slugs but produced better accuracy and smoother and more consistent feeding when using pellets.
Also, since you mentioned running pellets in your rifle too, with my tune above when I want to shoot 25.4gr JSB RD Monsters I drop the macro to 12 and valve to 4 which sends them at 935fps with excellent accuracy, and for shooting JSB 18.1s I adjust the macro to 4 and the valve to 4 which sends the 18.1s at 915fps. You can easily go slower and less energy with the 25.4s and 18.1 JSBs by reducing the hammer macro further, but those settings are where the pellets were the most accurate in my rifle.
