Maybe it would be better if there's not timeout for captcha in JD. Captchatrader has not timeout built in so when jd submits a request it (may) respond in any time. So if the hoster has a long timeout (over 30seconds) this solution avoids a waste of a resolution because of jd's timeout. If the captcha has expired it would load a new one in any case.

Captcha timeout in jd may remain but instead of reloading a new one the countdown would continue to negatives (red color for better see it) in order to alert human resolvers that the current captcha may be expired.