>*'Are there different types of carbon filters, some that would filter out chloramine and some that do not?'*

Sort of. As long as you're dealing with [activated carbon filters](https://en.wikipedia.org/wiki/Activated_carbon) they will provide the necessary components for the chemical reduction of chloramine. The difference , though, is whether or not they provide the necessary surface area of activated carbon *or* the correct flow rate to effectively reduce it **in one pass**. My guess, then, is that (at least in the eyes of the seller) this unit has either insufficient surface area *or* too high a flow rate to effectively reduce chloramines in the single pass.