In honour of the brave crew of Hr.Ms. Java 27-02-1942 † Battle of the Java Sea
I use Philip Sabin's solo rules.
So to clarify.
A high uncertainty bomber is at searchlight zones.
That means six MU bombers at six different searchlight zones.
At searchlight phase I test each of the six counters to see which is the MU counter.
When I find it I roll again for searchlight fix.
If I roll a 6 I know the exact position of the bomber.
When it is changing zones I roll for handoff.
If I succeed the fix continues.
If not it becomes a LU counter.
If you select to test a high uncertainty counter in a searchlight zone you get an automatic test for phantoms but every game turn you get 1 test per searchlight zone. The bomber counters will enter the J, K, L zone first. So if you did not eliminate phantom counters with radar searches beforehand you can now only check 3 out of 6 high uncertainty counters(HU) per turn.
The method you describe would only work on the border of 2 searchlight zones (so between J/M, K/N and L/O) or when not all HU counters enter the first searchlight zone in the same gameturn.
Things get better if there are less HU counters for a bomber. It goes like this. I mention the total HU counters for 1 bomber and the effect for the counter that is tested.
6 HU counters. On a 1 it becomes a MU counter otherwise Phantom
5 HU counters. On a 1 it becomes a MU counter reroll 6 otherwise Phantom
4 HU counters. On a 1 it becomes a MU counter reroll 5, 6 otherwise Phantom
3 HU counters. On a 1 or 2 it becomes a MU counter otherwise Phantom
2 HU counters. On a 1, 2 or 3 it becomes a MU counter otherwise Phantom
A MU counter result will get the searchlight fix test. Best case scenario is you get to roll 4 dice (good visibility with half or full moon or radar directed searchlights). You need to roll a 6.
You need a lot of luck to get your Nightfighter in a firing position when the fix can appear in the full width of your hunting zone. It's better to use the radar to eliminate some HU counters before they enter the searchlight zone. You will at the least eliminate 1 phantom with every radar search so why not concentrate on 1 side of the board and eliminate HU phantoms there?