What is meant by "proportional" and "smearing" in batterystats

I want to analyze battery consumption of an app and ran:

> adb shell dumpsys batterystats > dump.txt

Within the filedump I found the section I am interested in:

Estimated power use (mAh):
    Capacity: 3020, Typical: 3100, Computed drain: 1395, actual drain: 1510-1570
    Screen: 770 Excluded from smearing
    Uid u0a387: 364 ( wake=5.23 radio=0.0425 wifi=4.51 gps=349 sensor=4.88 ) Including smearing: 402 ( proportional=38.6 )
    Cell standby: 128 ( radio=128 ) Excluded from smearing
    Unaccounted: 115 ( ) Including smearing: 0 ( ) Excluded from smearing
    Uid u0a382: 40.6 ( wake=5.00 radio=1.40 wifi=34.2 ) Including smearing: 801 ( screen=684 proportional=76.9 )
    Idle: 27.4 Excluded from smearing
    Uid u0a83: 17.7 ( wake=0.240 radio=0.202 wifi=5.84 gps=2.33 sensor=9.06 ) Including smearing: 19.6 ( proportional=1.88 )
    Wifi: 10.0 ( wifi=10.0 ) Including smearing: 11.1 ( proportional=1.07 )
    ...

Each line contains info on "smearing", and if smearing is included part of this seems to be something called "proportional". These terms are not explained at all in the documentation.