I tried to find an answer in the previous long list of questions but couldn't locate one. When a word is followed unspaced by a series of superscript numbers, each enclosed in brackets, is the superscript indicator repeated for the second number? An example would be something found frequently in Wikipedia, such as California, where the  are in the superscript position. Are both bracketed numbers assumed to be in superscript if the indicator (dots 35) is only placed before the ? Or should the indicator be repeated for the ? What is the extent of "superscript mode"?
In UEB §11.4.1 Definition of an item, it reads "The scope of a level change indicator, that is, the symbol(s) affected by it, is the next "item". An item is defined as any of the following groupings: ..."
The last two bullets on the list apply to this question:
• Any expression enclosed in matching pairs of round parentheses, square brackets or curly braces.
• Any expression enclosed in the braille grouping indicators.
That definition seems to suggest the scope extends to a single grouped number —just the first number  —and doesn't indicate it would apply to the remaining symbols-sequence. Considering the braille reader's perspective, it may be assumed, but not certain the  would also be read as a superscript since it's unspaced from  and followed by a space in print. But I still have doubt and believe the superscript indicator should be repeated for the .
You are correct in saying that the superscript indicator would only apply to the first number. You are also correct that this ties in with the concept of an "item." You could treat each superscript number individually, with each number getting its own superscript indicator. Or you could use one set of braille grouping indicators around all the reference numbers at that location, adding grade 1 indicators as needed.
This question forced me to look at super and subscripts in different sections of UEB Guidelines for Technical Material and had wondered if the second superscript indicator would have the effect of adding another level above, making the  in a super-superscript position. But the grouping indicators seem to alleviate that worry. I think I'll go with the superscript indicator on each number. I would only need the grade 1 on the  since the second indicator —before the  —follows a number and is already in grade 1 mode, correct?