Chevron does not have 100% control over when the severance gets paid for R4.
They are counting on R4 employees left standing/EOI to NOT wait the 60 day waiver period.
IF AN EMPLOYEE WAITS the 60 day waiver period and signs say in middle of December the severance GETS PAID in JANUARY and will save considerably on Taxes and Chevron will be forced to pay that money on 2021's books
SAVE THOUSANDS in TAXES (esp if you have many years of service) : Don't SIGN THE WAIVER early, if you do, you will pay 1000's more in taxes come April 15th.
DON'T FALL FOR COMPANY PROPAGANDA and sign right away in your desire to get that money right away.
This is fully explained on Chevron's severance info pages in plain text. It even gives examples