they don't specify the number of lights to be counted
Correct but they
do specify that 15m spaced lights are in operation. That is a requirement. If the displaced threshold doesn't have HI centerline lights at 15m spacing then you cannot use it. (Like I said earlier I wouldn't be lining up from J in the first place.) What is the point of having such lights if you can't see them?
Why do you think that the section of runway that you're on isn't relevant?
The regulations don't state where the 15m spacing must start either.
Oh, it's not just my current airline but the two previous as well.