Willie Everlearn,
JAR-OPS 1, Subpart G - "Performance Class A". OPS 1 operators are allowed to reduce screen heights on wet & contaminated runways to 15 ft. - and include effect of reverse thrust in MOTM vs. TODA and MLM vs. LDA
. See
http://www.pprune.org/forums/showthread.php?t=201568 for more on how adviseable this is considered to be
Only other 2 euro-cents worth - rolling into the approach lights at the other end of the runway @ 40 kts. is generally survivable (not talking FCA, FAE, FRO et al here). Not advocating one way or the other here, but if you cut it down to sheer survivability on the majority of airports most of us operate from, I feel there might be a point in this. Sure, aircraft gets damaged, but everybody walks. Can you ensure that if you go at V1 - 10kt? Given the knowledge of performance that I've seen many pilots in the industry demonstrate (not dissing anyone on this forum, so keep the flame-throwers in their holsters), I doubt that even 50% would be able to use the AFM charts to calculate independent "stop" and "go" V1s, much less in the time available in the flightdeck for preflight prep.
However, the next time you de-rate, you might want to consider taking 4-6 deg. C off the max allowable derate - and there's your margin! It's easy to do and does not require altering the SOPs. Oh, and it will hold in a court of law - going at V1 - 10 won't (imho).
Cheers, Empty