My weight-gain diet...

The Mifflin-St. Jeor Equation:

RMR = 9.99w + 6.25s - 4.92a + 166g-161

The Mifflin-St. Jeor Equation explained:
RMR: Resting Metabolic Rate
w: weight in kilograms; if you know your weight in pounds, divide by 2.2 to get your weight in kilograms
s: height in centimeters; if you know your height in inches, multiply by 2.54 to get your height in centimeters
a: age in years
g: gender; 1 for males, 0 for females

RMR = 9.99*56.81 + 6.25*173.99 - 4.92*26 + 166*0 - 161
RMR = 567.5319 + 1087.4375 - 127.92 - 161
My Resting Metabolic Rate = 1366.0494
Calories to maintain weight: RMR*1.15 =  1570.95681
Calories to gain weight:  1570.95681 + 500 + 180 (lost during my 30 minutes of yoga , pilates, cardio) = ~2251

Actual results over the past 3 weeks:  Gain two pounds, lose two pounds, gain two pounds, lose two pounds, gain two pounds, lose three pounds, gain two pounds.  I just don't have the time to continually count calories, but instead I have focused on larger portion sizes, whole milk, whole grains, balanced meats, and more meals throughout the day.  If this gain-lose cycle keeps going I may have to be more strict about it.  My weight has not fluctuated this much in the past decade and even if it is only a few pounds, I'm not sure its healthy.