I have found related questions but my doubt remains and is best explained with an example. Consider the following sentence in a Finance academic article, where it is common to use the dollar symbol instead of the word "dollar":
A $12 midpoint followed by a $2 price revision should have the same consequences as a $18 midpoint...
I argue that the third indefinite article should in fact be an "AN", but my coauthor wants an "A". There is agreement about the first two usages of "A".
My argument: the way in which the last part of the sentence is read is "... same consequences as an eighteen dollars midpoint..." But of course it could also be read as *"... same consequences as a dollar eighteen midpoint...", which I personally find rather awkward.
Is there any guidance as to the best practice when a dollar amount is preceded by an indefinite article and a dollar symbol?
There is a question at this link on indefinite articles in front of symbols: What article do we use before a symbol? Is it "an @" or "a @"?. While it is a useful article, it does not address my question. Differently from that case, in my case it is not clear that the name of the symbol (what it represents) is read first. That's exactly the issue: if not read first, I should pick a or an depending on the number and not the symbol.
PS: As mentioned, there are several similar questions asked in other posts. However, the particular feature of my question is that there is a symbol between the article and the noun AND the symbol is pronounced after the noun. I believe there is added value in keeping this question as is.