Data point: was referred from my partner's personal Plat to a Gold. Put my Plat for existing account (I realised after submitting the app that I should've put my SPG Personal instead). App went pending (since I had applied for SPG Pers less than 90 days ago). Called and approved on the spot.
This is my second ever Personal Gold. The first one was closed last summer, around August if I recall (shows last reported on CreditKarma at beginning of September).
I will report if I get 25k again. Already got the 15k referral bonus on my spouse's Plat.