Funny thing.... the call from ATF for updated paperwork was for a sbr on form 1. The suppressor on form 4 that the tax stamp just arrived on made it through with no problems. They were both submitted at the same time with the same ammendment.
I likely have the same trust (you had to remove a sentence?) as you, twice now had to email amendment (have 3 others) but was approved 1 week after they got the amendment - twice now.