This is one of those things that non-teachers don't entirely get. If you work in an office, time is pretty flexy. If a meeting can benefit by running an extra 10 or 15 minutes, you just do it. But in most schools, when the bell rings, you're done. There is no little extra bit of time you can just throw into the work.
It concerns me a bit that you are going to require him to "With guidance and support from adults, explore a variety of digital tools to produce and publish writing, including in collaboration with peers." Did you know there are countries that don't teach reading and writing until kids are 7? Seven years old!