If the naming of the Word styles is _exactly_ the same as the naming of the ID style, your ID style should substitute for the Word style when the file is "placed" into ID. If the naming is even a little different, the Word style will be imported as a new style in ID and will carry (for the most part) any idiosyncracies which make the Word style different. This would still be OK if your ID "typesetters" then did a search-and-replace to substitute your desired ID styles. Sounds like the naming was somewhat different and that the S&R didn't get done.
I'm not claiming omniscience on this one. I just noticed you still hadn't gotten a reply and so thought I'd clue you in to what seems to be working for me as I strive to get ID style consistency from my imported Word files. Hope this helps.
(Oh, by the way: I'm running IDCS under XP. If you're running an earlier version of ID, perhaps that could be the source of your problem? It seems I used to have a much harder time with this process before upgrading from ID 2.1-ish.)