Refund amount increased after submission.

Long story short, I had to mail in my 2020 returns due to issue with 2019 return still not being processed. At the time I printed and mailed my 2020 return to the IRS, my expected refund was $3567. Now Turbotax shows my expected refund at $4791. Why did my refund amount increase? Also, I just found that my 2020 return is in the process of being processed. When checking "Where's My Refund", it recognizes the $3567 amount and not the $4791 amount. Will the IRS adjust my refund to the higher amount?