It follows on from the 1970s when expressing figures in units that simply reduce the number of printed digits were covered in training courses. Other manufacturers went for colour codes as an alternative.
Am enjoying it alas the spiders who were inside it at some time did not ,when I have done this one I have a pye 445u to do keep myself occupied as the rain has stopped me doing work on the allotment .And I am awaiting the 12k and 2k7 replacements for the dog bone resistors as these have vertically carbonized.
Regards
Robin