I've got the same flashmeter and found I can sync at 1/200 but the meter gives me 1/125 or 1/250. So I pulled off the back battery cover and changed the dip switch settings on #3 and #4 to the ON position (which is pushed up away from the battery). The #1 and #2 are in the OFF position (closest to the battery). There are markings but give me a yell if it it doesn't work for you. I turned the power off to the meter first, adjusted these two dip switches and BOOM, I have 1/3 steps now--100, 125, 160, 200, 250, etc.
G Holt