I don't think you understand what the problem is. Or perhaps I don't. It's not that the angles at frame 5 are incorrect, but it's that interpolating angles doesn't do what you want. So interpolate quaternions instead, which behaves much much better.
Ok I explain again just to make sure, thanks for you help so far.
Some frames have angles that are negative for example -179.9 when THEY should be 179.9 in order for the animation to be correct.
So when I key frame 1 as 179.9 and frame 5 as -179.9(the incorrect angle) maya translates between frames rotating 360 degrees (to get from -179 to 179) instead of there been very little rotation if the correct angles are used.
-179.9 is the same as 180.1 which would only cause 0.2 degress of rotation between frames like it should be.
Is there a reason the anlge is negative when it shouldn't be, maybe it's todo with been so close to 180.