jpeg:extent not working?

[boland]

First of all, awesome tool. However, it doesn't seem to work with jpeg:extent in version 6.9.2-Q16
It just doesn't seem to do anything, file sizes are exactly the same. Command is e.g.:

convert C:\Projects\background.png -define jpeg:extent=400kb -resize 388x188! C:\Projects\Resize.png

File size is e.g. 1MB. Tried both upper and lower case.

[snibgo]

I expect that "jpeg:extent" is relevant only when the output is JPEG, and has no effect on other compression methods.