look if VO need more some clarification from applicant they can call for interview after medical also. I can say 95% medical request raised over the worlds all CHC just 5% rarely VO called for interview after medical. it's depend on your application and NOC, even country too. I adviced you just follow e-case only.
read here another case:
http://www.canadavisa.com/canada-immigration-discussion-board/can-i-still-apply-b1-visa-after-canada-pr-and-i-filed-140-before-t69079.0.html