You may think about separate documents for the detail lines and imbed a single category view of them in the form. A table of the scale that you are talking about can be a coding mess when it comes to input validation, line extension and summarization. Then, about the time you think you’ve got it, someone wants to pull and summarize matching detail information across multiple forms… now you have to find and extract it all.
I have used the Midas Richtext dll to do something very similar. It allows you to copy a row from a table, complete with fields, to a new row. Any formulae associated with those fields can then be automatically adjusted to the new field names (although this is less relevant with R6’s @ThisField)