I found this sentence in a news article on Sunday:
Kolinda Grabar Kitarović, kandidatka opozicijske koalicije, na čelu s HDZ, bo vodila Hrvaško naslednjih pet let. Razlika med njo in Ivom Josipovićem je le dobro odstotno točko oz. med 18.000 in 20.000 glasovi.
"K.G.K., a candidate for the opposition coalition, leader of HDZ, will lead Croatia for the next five years. The difference between her and I.J. [the other candidate] is only a good percentage point[?]: between 18 and 20 thousand votes."
The phrase dobro ostotno točko seems to be either in the accusative or instrumental singular here. Which of these two cases would you say it is, and why isn't it in the nominative, i.e. Razlika je dobra odstotna točka? Would that have meant something slightly different?