Let' say my TA cannot find a particular fare and I managed to locate it on ITA.

From what I understand, one can paste the fare construction string code into the TA's GDS, right? Will the TA be able to pull up the fare then?

I asked my TA but she was reluctant to do that? She muttered something about back invoicing.

Thanks in advance and if you can point me in the right direction/additional reading material, I would be pleased. Still trying to learn more.