Whats the title of this Test document Kwaitek or its AVIA Ref No ?
This does not reflect the In service Boost ratings for the Merlin III. Its unusual in that In service MERLIN III climb rating was + 6.25Lbs boost not as +9 shown here. If its genuine then I believe its a 1 off RAE trial report investigating the feasibility of rating the Merlin to +9Lbs climb in preparation for this rating in the Merlin XII. Merlin XII as fitted to Spitfire MKII had +9 Climb
MERLIN III LIMITS from Spit I Pilots notes