This doesn't make much sense. I thought off -exchange was paying the same? I guess the hassle of dealing with ACA is not worth it.
Off exchange has the same rates, but they are not eligible for a subsidy. The subsidy given by the exchange is what causes the "out of pocket" premium difference.
In KG's example, the client could have saved hundreds per month by going on exchange since she qualifies for a subsidy. Same premium, she just doesn't pay all of it when using the exchange.
I think Gulfman meant that it doesn't make sense for a broker not to sell on exchange since the commission are required to be the same.
It may be that the broker sold her with a company that doesn't sell on-ex, though, so they want her to stay far away so they don't lose their commission, which is being a crappy agent, what goes around comes around in that situation.