Hi,
I have just tested on a simple box with animated twist modifier:
• Max timeline was 0-100
• The animated keyframe was on frame 100
• Exported an animated proxy with Corona Proxy Exporter 0.08
• Animated was enabled, frame from: 0, frame to: 48
Exported proxy was as expected, 49 frames in total, as 0 is also a frame totaling to 49 frames.
The +1 is expected if exported in this manner.