Consider these two examples: a 45- to 50%-a-year increase a $45- to $50-a-month deduction Here’s where the confusion lies with me regarding the suspensive hyphenation: “A $45- to $50-a-month deduction” means: a $45-[a-month] to $50-a-month deduction. That example above, with the suspension, makes sense. But: a 45- to 50%-a-year increase Apply suspensive hyphenation rules to this phrase: a 45-[a-year] increase to 50%-a-year increase Because the % sign is missing after “45,” it doesn’t seem as though the “suspension” logically connects here, as in the “$45- to $50-a-month deduction” example. Does this mean that the hyphen after “45” is totally wrong? I wouldn’t think so, because you need some form of punctuation to denote the connection to the “%-a-year” portion in the latter part of the phrase. We certainly couldn’t write: a 45 to 50%-a-year increase. There needs to be some form of punctuation after “45” to show a connection to the latter part of the phrase (“50%-a-year increase”). So, then, “a 45- to 50%-a-year increase” is technically correct, right? The omission of the % symbol is what has thrown me off, and “a 45%- to 50%-a-year increase” is simply an eyesore with two % symbols, especially when the phrase is not read aloud that way (that is, we are not saying the word “percent” twice; we are saying it only once after the second figure (“50”). That was my last question on this. Topic abandoned. Thus, exactly as written, the following examples are unequivocally correct, right? ...a 45- to 50%-a-year increase... ...a 10- to 20%-off coupon... ...45- and 55%-a-year increases... ...45- or 55%-a-year increases... ...will be offering 10- and 20%-off coupons... ...may be offering 10- or 20%-off coupons... Thank you. Very interested in your thoughts.
As I understand suspensive hyphenation, the formula is ABC- (connective) DEF-XYZ, means ABC-XYZ (connective) DEF-XYZ. Since "%" does not have a hyphen in front of it, it cannot strictly be omitted in this way. That said, in the context the meaning would be understandable in informal writing, but its ambiguity would not allow such usage in a legal or official text.