When you say "timed" I'm not exactly sure what you mean. There is time of injection pulse at the pump , time of pulse at the injector, time of injection in the combustion chamber, and time of actual combustion. There can be a 4-6 degree difference in lag. Depending on what someone is trying to check, "air timing" can be used to verify static timing, or factory pump timing marks can be used if they are known to be correct. A timing light can be used to check injection pulses on an injector line and a luminosity probe can be used (on some engines) to check actual time of combustion.
For Deere, Stanadyne gives time of injection pulse at the pump only, along with whatever range the automatic advance provides. Standadyne also gives specs per pump # of exactly what degree point the timing mark is etched on (and it differs). It also dumbs things down a little since when installing a pump -we assume the timing marks have been put in the correct place on a degree wheel.
One nice thing about JDB pumps on most Deere machines is an easily adjustable timing advance that can be correct on a running machine with no special tools other then a $10 plastic timing window.
My main point in regard to commenting was to the claim of setting the timing to "10 degrees BTDC." Regardless if that is a recommendation for pump degrees static timing (which equals 20 engine degrees at the crank), or for 10 engine degrees (5 pump degrees) . . it represents a problem on an engine if the advance is working properly. To the converse - it can be a short-tern "easy" fix for an engine that has a totally non-working advance.