Flightsafety, simuflite, etc. takeoff and landing numbers are part 91 in their checklists. If your landing u must multiply 1.67 to the 91 number. If your taking off and it's wet you must add 15% to the 91 number. Does a percentage need to be added to the checklist for takeoff numbers if it's dry to make it a part 135 Checklist? Please answer only if you fly a part 135 jet.
The way we do it:
First, APG. We use APG to give us a weight that we can land at given the 80% rule (it also gives us a weight for the wet runway numbers, which adds 15%).
Second, the FMS. We can use the 1.25, 1.67 or 1.92 factor in the FMS to give us a runway length. But by that point that number is pretty useless since the regulation just prohibits you from taking off at a weight greater than would allow for landing at your destination (given normal consumption of fuel, oil, etc.) within 60% or 80% of the runway length and factor the 15% in for a wet runway.
Also, we have our FSI/Cessna "checklist" (Flying the Cj3 for dummies) which gives us landing distances. If we REALLY wanted to be precise, we could haul the AFM inside and go into the performance section and do the work ourselves, but the software does it for us.
For takeoff, our takeoff distance (factored for wet runway and/or contaminants as necessary) just has to be equal to or less than the TODA, as I understand it. No factors need to be added because those numbers come straight from the AFM. Of course, if the numbers were exactly equal, we'd probably either wait for a dryer runway, cooler day, drop some bags, not take as much gas, etc. to get the required distance to be shorter to allow for some "oops" in the event of an aborted takeoff.
That's how we do it for 135 EOD ops. If we can't use EOD rules then we'd use the 60% factor. For our 91 flights with the owners, we use the 80% numbers almost exclusively.
Applicable regs for us: 135.398 (We're Part 23 Commuter category). That reg references 135.385 and 135.387. Those regs give us our 60% (or 80% for EOD) factor for destination and alternate airports. They also specify the 15% factor for wet or "slippery" runways at the destination.
Hope that helped some.
-mini