Getting a tab doesn't affect your # at all. I'll here are 3 options for the tab now and if you don't have to change your plan for the small tab all plans are eligible, but if you choose tab medium you need a plan of $30 or more so if your plan you have right now is $30 or more you don't have to change plans but if it's not $30 or more you'd have to change to a plan that is. For tab large you need to change to a large tab plan.
If you choose tab medium you'll have a $5 tab charge add led to your bill each month for 2 years or until the tab is paid whichever is sooner, the large tab is the same but a $10 per month charge. The small tab has no tab charge. All tabs have Koodo paying a portion of the tab at a rate of 15% of your bill each month instead of the 10% you get now.