I thought I had this figured out some time ago, but I lost the "handle" on it. When you see a direct link listing on eros, you can often detect a provider using multiple advertising names. No big deal, right? It is a handy way to check for reviews when you first strike out.

This is the link for Pamela

http://www.eros-dc.com/files/dc-penelope11-pamela1.htm

She evidently advertised as Penelope at some point in the past.

Within the last year or so, multiple advertisers have been showing up with the same prefix followed by different names. The photos and descriptions are different and the locations are not consistent. A recently noted instance follows.

http://eros-la.com/files/la-monserrat2-rubi1.htm

'monserrat2' is a prefix used a lot by providers who appear to be from the same area of LA. 'Christina' appears frequently on the East Coast. Most seem to be heavy travelers using "visiting" status only.

Is it the same credit card... address...agency? Any thoughts?

The Monserrat prefix we know goes for as many as 6 sets of EROS ads (search this board for more details). I have seen her ads both in LA and NY at the same time so I'm guessing she shares the ads with friends from time to time. There was also a discussion on the multiple name/number issue on this board as well. I think there's many reasons.
1. to avoid the stalker types.
2. to avoid reviews/rep.
3. to have fun. Hey, new look, new city, new name. Why not!!

search under the current name and any name that may be in the url.  Another tip is to google the number and you will see multiple links come up if you have a crazy poster on CL or maybe she travels everywhere and moves her Eros ad, or maybe she has 5 different name changes in the past 6 months.  All of this is good info to search on here.