I was just discussing this with a co-worker of mine. He wanted to use the word "totales" and I didn't think that was correct, so I immediately went to RAE to check but RAE didn't mention anything about it. Doing various searches we came up with very few uses of "totales" so he decided not to go with it, but is it really wrong to use that? It's for the sum of the rows in a table.
Total: singular. Totales: plural (more than a total).
For a single column in a table, its sum is a single number: "total".
For multiple columns, a row of per-column sums involves multiple numbers: "totales".