I have found a way around this problem of work taking much longer th emore upgrades you have. Although the reason behind this I'm sure is the fact that the more upgrades = more actual parts to their job such as faxing, shredding papers, filing etc., but it all leads to a longer work cycle. The way around this - if you can call it that, is to search for a peep in the beginning who LIKES work!! I have three families on the go. The first one had a father who loved to work - so did his wife but that was by pop up choice not mine. she was his third choice of wife. They worked like a dream! I never had to place them in their work place they just LOVED TO WORK!
My second family has only ONE who loves to work. It happens to be the mother this time, so hence the reason she only has two children. I have noticed a serious marked difference in the earnings as a result. On average this family earn 1/2 to 3/4 of my first family.
My third family has a father who likes dreaming ( seriously BAD choice on my part! ) getting him to work is like getting blood out of a stone. I've even change dhis career, but to no avail. AS a result the only earnings we have are from collectibles. I have to double up on them in order to amount any money of somewhat decent standards and I can neve rleave them to ''just get on with it''.

So... I would say to anyone struggling badly. change your family. Delete the first - sadly and choose another where at least one member actually LIKES to work. Or simply choose someone on level 2 to begin with and choose his/her partner CAREFULLY!!