Read Thread: Lucky coincidence
I tend to log that way too, but seeing this discussion I may just change how I do it. At least then I can see that I've missed a bonus box while I'm still in the field.
I had a box containing the bonus clue melt in a brush fire. Luckily, I had the clue to the bonus box in my BB notes so that I could find it (it survived the fire).
Since I have started using my smartphone while letterboxing I usually log online right at the box and then check right then and there for the next nearest box, as long as I have cell signal. While on road trips thru areas I am not familiar with I love the feature of Clue Tracker that links in Google Maps with the box's location to route me right to the nearest road to the box. It is not always the best route and the box's location might not be accurately listed in AQ or LbNA but it usually is good enough to show me an efficient route to find the box.