Well, the multipliers for maintenance vary widely from individual to individual. Maintenance might be a multiple of 18 for a male 21 years of age who is physically active. Maintenance for me is a multiple of 13.
You can use a multiplier of 15 and then subtract 500 calories per day from whatever that number is OR you can go with the numbers I gave you. No matter which you choose, adjustments typically need to be made. If you're losing weight too quickly (more than 2 pounds per week), you would need to adjust calories upward. If you're not losing weight fast enough (less than one pound per week in your case), calories would need to be adjusted downward.
I would recommend, however, that you not make any changes to your diet or caloric intake once you've decided on a number for THREE weeks. It takes the body that long to settle into new eating patterns and stabilize. At that point add or subtract 250 calories per day.
Just see how it goes. I'll help you adjust things down the road if you need help.
And, too, if you have any other questions, don't hesitate to ask! (grin)