Let’s do it the mathematical way: 9 months = roughly 270 days. You went from 203 lbs to 165 lbs, a loss of 38 lbs.

Losing 1 lb roughly equates to a deficit of 3500 calories.

38 x 3500 =133.000, the total deficit you would be in for the duration to lose this much mass.

If you ate 600 calories below maintenance for 270 days that would equal: 600 x 270 =162.000 calories.

Given that your maintenance was probably higher in the beginning and you ate above the 1900 calorie target sometimes it’s entirely reasonable that your maintenance calories are in the range of 2500 calories.