help - internet xfer speed to data xfer limit?

[halome]

Ok, here is my dilemma/question. I am comparing 2 hosting packages.

SOME BACKGROUND INFO

HOSTING PROVDER A -
Allows me 500gb of data transfer a month (which I can divvy up between all domains I own as I see fit) and the server has a 100gb uplink (this uplink is shared with however many people happen to be currently hosted on my same server at any given time and can vary - they do not specify a transfer speed outside of the uplink speed of the server - or the amount of people/sites I might be sharing my server with at any given time).

HOSTING PROVIDER B -
Has no limit on data transfer a month but has a max transfer speed of 15mbps, which is automatically divvy'd across all of my hosted domains.. (I plan to host quite a few as I am designing websites and hosting them for people.)

QUESTIONS
1. Can I run out of speed if 15mbps is divv'd up across all my sites and I end up having too many sites running at any given time, or no because they should all get 15mbps regardless of how many sites I am hosting because of the lack of a limit on data transfer a month...?
2. How can I figure out which one will run faster? Or calculate the varying speed based on different scenarios (ie...hosting A with 100 hosted domains/sites vs. Hosting B with the same)

CONVERSIONS LISTED ON THIS SITE - convert-me.com/en/convert/data_transfer_rate/

CONVERSION 1
If I divide 500gb of data transfer a month by 4 (for 4 weeks in a month - which is 125gb) and place that number into last box on the bottom table "Transfer Rate per Different Time Units" - "Gigabyte per week" - and click "convert", top 3 tables turn "megabits per second - mbps" to 7.101, Megabytes per second - MB/s" to 0.8466, and "second per megabyte" to 1.181.

CONVERSION 2
If I clear the table and submit 15mbps into top left table for "megabits per second - mbps" and click "convert", I get 1.788 for "magabytes per second - MB/s", 0.5592 for "seconds per megabyte", and 1,056 for "gigabytes per week"

:?: ANSWER/CONCLUSION :?:
*****Does that mean that this is a correct calculation, and that in essence I am getting more speed/data transfer from hosting provider B than A..., in that over the course of a months usage, 15mbps transfer speed is equivalent to about 4,224gb of transferred data a month? And that it would take approximately that many gb (1056gb/4,224gb) of data xfer a week/month to go over my allotted speed???? (Obviously 1056gb a week/4,224gb a month is way more than 125gb a week ((or 500gb/mo)) Hosting provider A allows...) Or am I misunderstanding something here?****** :idea: :?:

PLEASE SOMEONE HELP! I HOPE THERE ARE A LOT OF SMART PEOPLE OUT THERE, CAUSE I AM DYING TO FIGURE THIS OUT, LOL...THANKS TO THE SMART PEOPLE OUT THERE IN ADVANCE FOR HELPING ME WITH THIS!!!! :!: :!: :!: