I first have to tell you that I truly admire and respect your sensitivity and loyalty to your Realtor. I don't think I've EVER had a client calculate the amount of time I dedicated to them. But you raise an interesting question.
On one hand, if your Realtor wanted or expected to receive a 'minimum' commission, or didn't think she would be treated fairly by her MLS co-broke commission, then I would think that she should have discussed it with you upfront. On the other hand, if you truly value her services to you, then perhaps you could consider paying her a 'bonus' at closing. You are definitely under no obligation or duty to do so, but I believe in karma, or "What goes around,comes around."
Thank you for your most refreshing comments and question!