Processing.Table columns should be typed as INT or FLOAT if you want to do maths with them:

table.addColumn("name"); // defaults to STRING
table.addColumn("count", Table.INT);
table.addColumn("height", Table.FLOAT);

If you don’t do that, trying to cast the value on the way out:

inst.getFloat("total")+1);

Seems like it’d work. Nope.

(Processing 2.2.1)