I have seen differences in procedures for upgrading and d/grading a/p's in different companies which I have worked. In BA I seem to remember that I could upgrade to 3B based on a satisfactory rampdown or 'autoland 40' or whichever test system a particular type may have used. However, where I am working now I have to d/grade and call for a standard app/landing for a nav light change (slight exagerration). We use an in-house all weather ops manual (AWO) written by engineering but stolen from another airline. The guy who stole/reprinted it is a bit of a plonker so it makes interpretation difficult (it was probably fine before he messed with it!!)
was there something specific which prompted your question??