Bottle nipple too fast?

My 2 month old is EBF and when when first introduced a bottle to him at 3 weeks he was able to chug it down in like 20 seconds. We got bottles with a slower nipple flow and it would take him more like 15 minutes. Now at 11 weeks he's starting to get really frustrated and refusing the bottle after an ounce. I tried the faster bottle yesterday to see if that could be the problem and he still took an ounce in about a minute. Is that too fast? When he nurses he is done in about 10 minutes. How fast is too fast for a bottle? Is it only a problem if he spits up and seems uncomfortable afterwards?