In your first case, have you set allowPanningOutOfDefaultRange and allowPanningOutOfMaxRange to YES for each axis? If not, this would explain why the chart refuses to animate when moving to a larger range - it would take the axes past their bounds. The axes should still animate OK when you go from, for example, a month to a day's view of your data - as this is within the range of the data.
In your second case, are you calling redraw on the chart as soon as your reload completes? If so, can you delay this call until after the animation has completed? There may, again, be issues with restricting the range to that of the data, without the aforementioned BOOLs set to YES, cutting the animation short.
Let me know how you get on