Your formula is wrong.

I removed all the headers and just showed the detail line.  The misc charge shows up three times for each invoice.  All the other line items only show up once,  Any ideas?

Probably a join creating a one-to-many link.

Agreed - join is the likely culprit.  If you have comments (table OECOINO) in the join, the connection happening behind the scenes creates one record for each invoice line / comment combination.  So if you have 3 comments, you would have 3 records and Crystal is adding the value each time.  This is solvable with a formula, but much easier if you just use the data from the header table.  OEINVH.INVMISC should have the total of all misc charges.

Agreed - join is the likely culprit.  If you have comments (table OECOINO) in the join, the connection happening behind the scenes creates one record for each invoice line / comment combination.  So if you have 3 comments, you would have 3 records and Crystal is adding the value each time.  This is solvable with a formula, but much easier if you just use the data from the header table.  OEINVH.INVMISC should have the total of all misc charges.