Turn/mill between spindles Mazak i-200S Matrix II

I'm trying to turn and mill between spindles on a Mazak Integrex i-200S. I can use M511 for both but when I go from a turning operation to a milling operation, my C and U axes lose synchronization by almost one degree. I will be clamping onto a fixture so I do not want to have to unclamp, re-position and re-clamp. I've also tried M514 but this only works for milling. Here's the code I'm using to test this:

G0G91G28X0.0
G28Z0.0Y0.0
G28B0.0
M901
M513
M200
M300
G28C0.0U0.0
G90
M202
M302
M511
M203S500.
G04X5.
M205
M200M300
G90G1C100.F1000.
M513
M30

Does anyone have a sample code I could look at or anybody have suggestions to try?