The point I was trying to make was that it doesn't matter exactly which point you stop for the transition so long as you stop in the same place in both parts of the test where that transition is seen. I got the same borate result (same number of drops in the second part of the test) regardless of the transition point I used (just barely blue vs. a more solid blue, for example) so long as I went to the same point in both parts of the test. My five tests even at different transition points all gave me the same borate result within one drop (actually, 4 of the 5 were exactly the same number of drops). Basically, if you go "too far" in the first part of the test, then it is exactly compensated in the second part of the test if you go to the same visible point since what you are trying to measure is the delta that happens after you add the mannitol. The exact transition point from which you start in the first part of the test and end in the second part of the test isn't important (since even a hint of blue is beyond that needed to measure the borates properly).