Yep this is correct. Adding disparate units is almost always nonsensical. You can confirm with a scientific calculator like insect: $ insect '5s + 10MB'

Yep this is correct. Adding disparate units is almost always nonsensical. You can confirm with a scientific calculator like insect: $ insect '5s + 10MB' Conversion error: Cannot convert unit MB (base units: bit) to unit s $ insect '5s * 10MB' 50 s·MB