You are correct they do differ some....but the key to them both is the same...we do not want to lose anything on the parent patent...336...that could effect the following one...148... so as not to lose the earlier filing date of the parent....336...
As far as the response time, it is 2 mos for us to respond to the PTO...unless we request an extension. Once we respond...hopefully with a granted sit down, face to face meeting... the PTO can respond with their answer without a real due date...they really take all the time they need...sometimes it's only a few weeks sometimes it is months based on the complexity of the issues at hand.