These stats are for the Model I, and is for two 10 digit numbers. The Model I did in fact use table look ups for math, except for divide (add table was at locations 300-399, multiply at 100-299). The Model II had circuitry for addition and subtraction, but still used table look up for multiply.
As odd as all of that sounds what you would find most odd was that the machine was not fixed word length. That meant that you could add a 100 digit number to a 200 digit number. The other oddity was that each addressable memory location was actually 7 bits, one of them being a parity bit.
The 1620 was my first computer and those two oddities were initially hard to overcome as I moved forward in my career.