K8061 response time

The website states that the K8061 has a response time of ~4ms. However, the Velleman website also states that the VM140 (the pre-assembled version of the K8061) has a response time between 21 and 48 ms. So, which of these two is true?

Is this response time different for the TTL outputs versus the analogue outputs? How does one go about measuring the time between issuing a command and it taking effect?

We are very succesfully using the K8061 in out Micro-Manager project (micro-manager.org, an open source microscopy software) to control laser output, however, the response times are a critical issue.

Thanks!

Using VB and the function OutputAllAnalog I archive 3ms time on Analog outputs (changing all outputs simultaneously).