As an MOT tester, let me tell you something that I have learned from my twenty years in Motorcycle MOT stations.
1) Most MOT testers don't test the headlight further than "It works" and it's not pointing at the floor or pointing into the sky. This is because it's a two man job to use the MOT beam tester.
2) Most MOT testers don't understand how to use the beam tester. And they haven't known since they did their MOT course decades ago. Let alone understand the charts and rules that relate to them.
3) It's quite normal for your MOT tester to not even be a mechanic. Or even have a bike licence. It's quite common for the parts guy or a random salesmen to be pulled off his desk to do an MOT when the mechanic is too busy.
The DSA have very little time or respect for Motorcycle MOT's. They're all car and truck guys and see Motorcycles as weekend toys. This a good and bad thing.. Otherwise you'd have emission tests, massive mirrors and failures for engine management lights etc
There is your inconsistency.