I haven't seen any conclusive evidence that supports such a conclusion (i.e. blood tests), but Frances may have a valid point in regards to UVB peaks and rather deep valleys within the 295-335nm range, and I most certainly wouldn't be the one to argue it. While there is an obvious spike around 312-313nm, there is virtually no measurable UVB within the 315-330nm range and very little afterwards. Now, if the MVB were placed at a closer distance it would certainly boost UVB levels, but I'm uncertain as to what type of affect it would have on the UVI number or the UVI to UVB ratio (Frances stated that the irradiances were not to scale/taken at the same distance.).