Static RPM limits

[Degrazia4741]

Advice/opinions appreciated!
My engine had c9nsistently produced required Static RPM between 2275 (min.) and 2400 (max) until my last flight
My last Static RPM was 2200, and lift-off RPM of 2400 RPM instead of 2500+ and Fuel flow 14.3 instead of 15.1 gph

Following that flight, A&P rechecked Mag timing/confirmed 25degrees BTDC
Annual 4/2023 (compression 78-79/80). Borescope confirmed Valves good cond./cyl walls good crosshatch.
Oil use 10 hrs/qt
-Piper Cherokee Model:1968 PA28-180 D
-Engine Lyc 0360-A4A (Roller Tappet) FACTORY Overhaul 2007 (TTSOH 1540)
-New Intake tube gaskets Yr. 2022/ just confirmed no blue fuel stains on intake system
- confirmed no leak in primer system and no loose primer lines to cylnders
-at 3500 MSL Full throttle/Mixture Full Rich produces 2670+ RPM

- Today confirmed Throttle & Mixture cable attchments at Carb are secure and fully move levers to stops at Carb
-Today, did a ground Static Run-up resulting in 2200 max Static RPM (min should be 2275). Also tried full Static
Run-Up on each Mag/separately resulting in 2000 Static RPM each Mag (Slck Mags 200hrs since overhaul 2021)

Any advice as to possible cause of below Minimum Static RPM……Or futher cks/evaluation of issue!?
Thank you

 

[Dennis]

 

[philiplane]

 

[TEG916]

 

[Degrazia4741]

 

[140B]

 

[magman]

 

[Degrazia4741]

 

[magman]

 

[140B]