It seems that White 52 was a mistake - too early. He was probaby too fixated on the fact that White 58 was the only absolute ko threat around.
Why was it too early?
The most important factor is the size of the ko, and thus the size of a move. As the article explains, the formula for the deiri value of any move in a ko is A x 2/B where A is the total deiri count and B is the number of moves needed by both sides to finish the ko - three in the case of a normal ko, four for a two-stage ko, four for a one-move approach ko (yose kou), five for a two-move approach ko, and so on. Since this denominator is based on miai counting (SL again!), the numerator 2 is to convert to a deiri value.
In the present game, therefore, the value of a move in the ko is 36 x 2/4 = 18. Which is pretty big.
But on the basis that a move (by miai counting) in the opening is worth 2 x komi (2 x 6.5 = 13), which converts to 26 deiri points, this early there should be a move in open field of some size similar to that, and so bigger than the ko.
White seemed to recognise this at once by answering at 62 instead of continuing the ko. Black was obviously aware of it all along. In fact the next move in the ko was not until move 149! Every move up to then was considered worth more than 18 points. It is instructive to look at the game and see why. In many cases it is obvious - although generally moves in a game may be considered to decline inexorably from 26 down to 0, hotspots occur during fighting where the value can briefly be much higher. Slightly less obvious are the cases where a move may not instantly look big but it has big follow ups.
Ironically, White lost this game when he ran out of ko threats, on move 169.
The full game is available here.