Why does compress increase the length of an inserted nozzle/coupling?

[johcatrac]

When we work with compress design, sometimes it can be seen that compress increases the length of the nozzle or coupling on its own saying the length provided by me is not adequate. Why does it do this? What could be the underlying justification?

 

[doct9960]

http://www.codeware.com/support/faq/1079.html