I would imagine that more goes into your approval than just the score. What is your Experian FICO 8 score? Also, how's the rest of your profile - utilization, inquiries, etc?
I got the Blue Delta about 2 weeks ago with EX-650, was also approved for the same 1k SL. I then also applied for the Gold Delta yesterday and was approved for 5k. Only difference between the weeks is my Util % changed from 9% to 6%