I have to say I've never been too worried about getting these additives exactly right, seeing as on many types if you've got the autothrottle in, you don't apply them. I feel most pilots can do a better job with the thrust than the autothrottle can, anyway...
For most landings, you have a good power-to-weight ratio (<MLW) and, *if you're stable*, can regain airspeed pretty quickly if necessary. The spread of speeds available is generally only 15kts, from Vref+5 to Vref+20. When Vref is 150kts+, I don't feel the need to add much more, especially if the runway is approaching limiting length. Overruns due to excess speed on T/D, prolonged flares, wet runways, tailwinds, etc. are right up there on the list of accidents that keep repeating themselves...
If it's a gusty day, keep on top of it!
