Welcome back, Dick!! ...Should've known a blue fish would get you posting again.
Interesting comment that Shusui generally do not have increasing Hi. The reason I thought there might be more Hi to appear was the way the speckles trailed in a "brushstroke" along the flank in line with the thicker Hi. I have watched Hariwake with flank brushstroke patterning increase color over a period of years, with the spots of color becoming joined, and some how gained an impression that flank patterning is subject to increasing that way. (I can't say I've ever read anything particular about it.)
Soelistyo: You have certainly put weight on him. Definitely improved. I am liking him more. The scale alignment remains good (although not perfect) and I like the soft bluish-white color. You've not had the head darken and the yellowish tone is not too strong... maybe he will soften to a nice ivory on the head? Since it is male you may not get him to a huge size, but male koi are so often the more graceful swimmers in a pond. I think he would make quite an impression in the pond ... does he dash at pellets, but hover out of the way of the crowd at feeding time?