Hi There,
I too have been having some issues with the promoted gigs feature and I've noticed that for some keywords you can clearly see on the 1st page there are "ads" being displayed clearly indicated by the word "ads" while for some keywords there are no "ads" on display. You can look at some of the attached images below it seems they are having some issues with the feature because I too have noticed a decline in sales from the "promoted gigs" feature. I've tried to tweak the settings but to no avail.
I think the problem may be stemming from one of two things:
1.They are having some technical issues with the feature
2.They are scrapping the feature for certain services that probably don't make them as much money and allocate all their resources to services that do.