Yes, I mostly use the NIV. The New Layman's Bible Commentary which was written nearly a decade before the NIV appeared used (I think) the RSV translation. It says "full number" and the writer makes no comments that the Greek should be translated otherwise. I have a Greek Interlinear Translation copyrighted in 1969, before the NIV, which translates "fullness" as "full number" So, if there is an error in translating and interpreting "fulness" it is not all due to the influence of the NIV.
"Full number" does make for a somewhat strange statement from Paul. That no more than a certain number of Gentiles will enter the Kingdom, and then the Jews will began to come in. Johnson's Notes interprets "fullness" as "the greater part of", which makes better sense to me than "full number". Johnson seems to interpret the passages in question, as you interpret them. That Paul's prediction came to pass shortly after he wrote Romans.