This is pretty normal. Upgrading earlier is actually very lucky. Out of my 4 refines only 1 of them upgraded before 900/1000. The rest usually required 990~/1000, thats why I recommend making sure you have those 1353refines to upgrade instantly from 7 to 10 without counting on luck. If you get lucky, you have some refines for next eq piece, if not, you arent losing a lot of wish credit. And by waiting you arent losing anything either.