Well, for one, you could import from the file into itself.
But what's wrong with exporting/importing, anyway? The advantage here is that the Export dialog allows writing pre-summarized values, which in other scenarios are a bit more convoluted to extract.
If you write a script that exports to the Temp folder and re-imports, this can be done totally seamless, and you don't have to worry about cleaning up the temp export file.
In replying I'm trying to imagine what you are doing this for, and I assume that maybe you need to capture a frozen in time set of values. If that's the case, I think what I would do would be to pass the sub-summary values into a static field in the target file using the GetSummary ( ) function. As this is likely to be a periodic task, and as you are passing data from one table to another, you may need to set up a script which you can run whenever needed. Alternately, if you simply want the figures posted automatically when a record is created in the target file you may be able to set it up as an auto-enter by calculation operation.