Hi. I went through this process with the same assessor last July. I asked the same question, because, after making soap for 4 years and merrily sloshing in essential oil till it smelled nice, the rules for assessment had not come up and I found no info googling the questions.
I was told that it isn't oil weight only, it is in fact oil weight plus sodium hydroxide weight plus 10% of the water weight x whatever % of EO you are putting in. So for me working on 600g oil weight plus 86g SH, plus 10% of water , 17.2g equals 703.2 x 1% equals 7g near enough. My understanding is that 3% is the maximum oil weight even if combing oils though some have lower limits. So my lavender and rosemary soaps I use 21g, lemongrass, I found 2% or 14 g was enough, similarly my sandalwood. Cinnamon leaf oil has a restriction of 1% max so 7g, and it still knocks my socks off at that level. My mint and tea tree 14 g and 7 g respectively and orange and patchouli, 14g orange, 6 g patchouli and 1 g lemongrass. The orange soap is the weakest, I use a 5 fold oil, 10 fold would be better but it is hugely expensive. The others are all pretty pongy. My concern if anything is that I use too much essential oil as it is the single most expensive element of the soap. So, that is how I was told to do it by the same assessor and I am now fully assessed and reasonably happy with the soaps. I think you can make changes to the recipes for an admin fee so getting certified doesn't completely set them in stone.
Hope this helps. I found thexassessor a bit slow to reply sometimes too, but they will eventually and were quite helpful when they did.