Question about Linkedin and positions

So I'm just curious, what's the best way to update your Linkedin profile when you move into a new position at your current employer? And also for populating your profile with past positions?

You can create a new position in your profile, but if you've been at your current employer for awhile than all of your positions show up as seperate entries with seperate durations. For example, I've been with my current employer for about 18 months and have had 2 positions. I was at my previous employer for 5 years and had 3 positions. So if I populate Linkedin with all of my positions individually than my profile will have 5 positions over the past 6.5 years or so, each with relatively short durations. In my opinion it sort of makes it looks like I've moved around a lot. But if I just create a "master" entry for each employer and then note the various positions in the description field, then you end up seeing the total duration that I was at each employer and the reader can view the descriptions to see the various positions I've held with that employer.

Thoughts? Does that make sense?

Secondly, this question also applies when populating your profile with previous jobs. I was with my first employer for 9 years, so if the recommend approach is to create individual position entries, should I go back and list each position with all of my previous employers, or just the last position I held there?

Hope that all makes sense.