Outtake from Rhyminsimon's training simulator, he uses these coefficients to account for the elastic effect:
Trained Skill Elastic Skill
JS DR 0,011
JR JR 0,000
OD HA 0,007
HA OD 0,050
DR HA 0,005
PA HA 0,030
IS ID 0,001
ID IS 0,020
RB IS 0,020 ID 0,010
SB SB 0,000