I cannot find it in the newer 3GPP docs. So...
To calculate Transport Block Size we this use:
Note: I TBS = MCS
But I found that if we use only one sub-carrier (single-tone) in NB1 we cannot use 11 and 12 MCS.
Mapping between the MCS index, the resource units and the TBSin bits for uplink transmission. For single-tone transmission, MCS indices 11 and 12 are not used. 
47 redirect me to
3GPP, “TS 36.213Physical layer procedures”, version 13.3.0,November2016. [Online]. Available: http://www.3gpp.org/DynaReport/WiVsSpec--690063.htm.
But how about category NB2? They added 13 MCS. Is it omitted too? Or maybe they moved line from 11,12 to 12,13?