I noticed the size difference as well, but comparing last year‘s Storm Blue to this year‘s Plum, they appear to be the same size. Plum is a half gram lighter FWIW.The green lake sports band feels thinner and more flexible, sits on hole 3 instead of green 7 hole 2.
My guess is the taller watch causes the band to feel bigger, and the lugs may sit closer to your wrist as well with the thinner series 10?