Caller Display is worth it's wait in GOLD.... But that 5% you talk about is a lot higher when you advertise you No for business and have Freephone No's(cheepskate's) ..
I a long time ago put my home No as a fax No in a add due to having a fax machine connected to it(stop shouting"silly sod") But that came back to haunt me big time...
About 10 attempted advert fax's a day at one time
They send them faxes out at night as well when cheaper call's
Happy now because as you say 99.9 % of "seller's" are No "witheld"...