Jose, are you sure the Current/Nova fixture is T5HO and not T5NO? Your results look a lot more like NO results than HO.
The effect of putting aluminum foil in the T8 fixture is about what I would expect - it doesn't take a sophisticated reflector to double the light you get compared to no reflector at all.
In general your results, except for the Current/Nova data, look consistent with mine. There is scatter in the data, for sure. But, the charts do allow you to get in the right ballpark with lighting, something I don't know any other way to do.