@chaz there's a few sneak preview vids of the new 2020 version over on the Twinmotion YouTube channel, apparently plants and people are to be much improved, along with other enhancements, it will be interesting to see what price point they start at, and whether they go down the route of subscription, or perpetual license ???
As for what you're giving your clients, if they want 100's of renders, you should be charging them £££s for this service, its a fine line what you 'give for free' trying to win work, and where the line is to start charging for revision after revision after revision.