Several comments if I may ..
Your version was what they termed a "performance landing" as it resulted in a shorter roll
Generally a reference to "performance landing" infers max effort, min distance from the screen. This infers min POH approach speed, generally 1.3Vs, min flare distance and max braking. GTE knows all about that stuff.
While there may be operational reasons to add a bit of fat to the approach speed going into the flare, in general, ANY extra speed is counterproductive if the aim is to achieve a min distance landing ... you have some concern about what lies past the runway head ...
Re speed adjustments if the POH doesn't provide guidance, one should check the PEC .. just to make sure you don't get into tiger country .. not usually a problem unless you are back near the stall.
add half the gust factor to the POH speed
Perhaps misheard in respect of common OEM heavy guidance, which is
half the steady wind plus all the gust to a maximum additive of 20kt.
Reasoning is
(a) steady wind is predictable and the low level gradient, in the absence of obstacles and the like, is fairly predictable ... usually following something approaching the usual FT and AFM 1/7th power relationship. Adding half the steady wind is an attempt to model this in a simple manner for line operations.
(b) gust is statistically unpredictable .. so it follows that a more conservative approach to additive be followed.
(c) max 20kt is a sanity check on the normal landing factor for heavies of 1.67 .. be careful with lighties as the factors are generally somewhat smaller. 20kt also reflects an old (ancient ?) UK BCAR AFM requirement which imposed that as a maximum additive.
Some discussion can be found in various threads including this
old one ...
nothing I can see in the POH that says this
The POH should have words of wisdom regarding the technique upon which the landing distances are scheduled. Otherwise a read of
the Flight Test Guide might be useful.
and will also dictate a performance penalty to the landing charts.
Generally none .. that's the reason for the 20kt limit.
jet engine throttle response isn't as rapid as piston engine
That problem went away years ago following a number of approach prangs where engine RPM was allowed to be too low. The simple expedient of requiring the engines to be spun up (typically above bleed valve closure) gave good response.