I believe the practice starts with resistors, and because of differences in use of . and , and the fact they are hard to tell apart, the units are placed in stead of the .
ie 1,500 ohm -> 1k5 ohm
so 2k8 is 2000 +8,
2k1da3 would be 2013
The way people seem to reckon it is 2k8 = 2 * 1000 + 8 = 2008
On the other hand, if it were 2k8h then it would be 2800 (2 kilo, 8 hecto).