Ethereal timings vs ping timings

Hello,

I'm testing an embedded ethernet device and when trying with the ping command, I have a different timings between reply timings indicated by the ping command in the dos window and timings indicated in the ethereal (time delta from previous packet)

For example for the first reply I got "time = 9ms" in dos window while in ethereal I have "time delta from previous packet = 0.00055 s"

Why this difference?

Thanks for your help.

Anis