In TD1 form, does the "More than one employer at the same time" part has anything to do with people who quit and join?

Could anyone please explain a question about TD1 form for me?

I changed jobs twice this year, aka, I have worked for 3 employers in 2021, but I never had more than one job at the same time, meaning I quit the 1st job and joined the 2nd company, then quit the 2nd company and joined the 3rd.

Now I am filling the TD1 form for my 3rd employer this year, and there is a section saying

If you have more than one employer or payer at the same time and you have already claimed personal tax credit amounts on another Form TD1 for 2021, you cannot claim them again. If your total income from all sources will be more than the personal tax credits you claimed on another Form TD1, check this box, enter "0" on Line 13 and do not fill in Lines 2 to 12.

It emphasizes "at the same time", which is not my case, so I guess this section has nothing to do with me, is that correct?

If yes, however, I will file three TD1 forms with the line "13. TOTAL CLAIM AMOUNT" filled with an amount for this 2021 financial year, I am wondering if it is OK?
It seems that I will claim the credit amounts for three times, which is wrong.

For my 1st employer, I filled the form last year and resigned this Apr.
For my 2nd employer, I filled it this Apr and resigned this June.
For my 3nd employer, I am filling it now.

Thank you for any help!