Data point:
Applied for VISA and Amex in link #4 using 2 browser at the same time. The first one was instant approved but got an error for the second. Reapplied for Amex several minutes later and got approved. After 60 days applied for CitiBusiness, went to step 3 and received a denial message. Recons by writing a letter and sent to Credit Card Review Department, 5 day latter, received a phone call from SD, the rep said that my application was approved but only 1K.