If the I2T value is shown in the S600 oscilloscope then the units are increments. What's the reason for that?

The I2t resolution is built from: 

Scaling i2t = 688537600 in the scope is 100% I2T if ICONT = DICONT of the amplifier. 

If ICONT is 0.5 DICONT for example, then the value is 688537600 * 0.5 * 0.5.

If FOLDTIME differs from the default value 16 ms for example, this has influence to the calculation as well: 

688537600 * (ICONT/ DICONT)^2 * FOLDTIME / 16