I think some crew here are confused about 1.67, 1.92 and the 15% buffer for wet runways, or so it appears by my interpretation of comments made. I don't believe pre dep or inflt has anything to do with the above figures. 1.92 is based on the ACTUAL dry rwy ldg distance, giving you your REQUIRED wet rwy ldg distance.
If you go to your landing distance tables for what ever LDG WT, Temp, El etc figures you'd like (dry rwy) and then divide that number by 1.67 you should have the actual ldg distance acquired via the manufacturers flt testing. Multiply that actual ldg distance by 1.92 and you get your required wet rwy ldg distance. If you multiply your required dry ldg distance (fully factored 1.67) by 15% you will get the same distance. I've done this for my type.
Again, 1.92 is the factor used for the actual dry rwy ldg distance (not factored), the 15% is the buffer on the required dry rwy distance (factored) that gives you your required wet rwy ldg distance. It's the same!