1) Shutter speeds are rounded off to make them easier to say, remember, calculate halves, etc. The true shutter speeds would be 1/2^x
1, 1/2, 1/4, 1/8, 1/16, 1/32, 1/64, 1/128, 1/256, 1/512, 1/1024, ...
I'd guess that 1/60 is probably within the accuracy of the shutter at 1/64.
2) It won't be fixed. Though I might ask, why is it a problem? How has it affected your photography?
3) 1/64 is the nominal speed for 6 stops below a 1 second shutter speed.
1. Why is this?
2. When will the problem be fixed?
3. Which of the two values is the true speed?
1. I have no idea! I have shot a 1Ds Mk III for a long time and have never seen this or at least I never noticed it.
2. It isn't a problem anyway so there will be no fix. The main reason is the 1Ds Mk III is a discontinued camera and will not likely recieve any updates.
3. Really? You can tell 1/60 from 1/64?