If you make a table called Max Record ID number and enter a single record in it, it will be [Record ID#] of 1.
Then on your details table make a formula numeric field which calculates to 1. The formula will just be 1.
Then make a relationships to that single record table and then make a summary field of the maximum of the [Record ID#] in your details table.
Look that up back down to the details table
Now the details table always knows the highest record ID# which has been used so far. or if you prefer, you can get the maximum of that other random number data entry number you have been using.
