I did the same thing for someone and with a 1x1 bitmap, there is at least one switch that takes 12s to complete, I'd say making the bitmap a bit bigger is better/safer.
I wrote a report about it and it didn't go through, I was reporting just in case but the timing are consistent as you make the bitmap bigger so in the end that might just be normal and it's just a bad idea to use that small of a bitmap.
