Datetimeadd function issue

[L_T]

Hi all, 

I have to create a payment schedule using start date/end date and number of payments during the period. 

The data are:

- Start Date: Nov 5, 2017 

- End Date: Mar 5, 2024

- 39 payments

Using these data, I can derive the each payment occurs every 60.842105 days. 

In Excel, I can add the above number to the start date and I precisely get to Mar 05, 2024 after 39 payments.
However, when I use the datetimeadd function in Alteryx (using exactly the same parameters), my last date would Feb 02, 2024. Below the differences.

Any idea why Alteryx does not return the same schedule as Excel? And what would be the best method to fix it?

Thanks in advance 

Alteryx	Excel
05/11/2017	05/11/2017
04/01/2018	04/01/2018
05/03/2018	06/03/2018
04/05/2018	06/05/2018
03/07/2018	06/07/2018
01/09/2018	05/09/2018
31/10/2018	05/11/2018
30/12/2018	04/01/2019
28/02/2019	06/03/2019
29/04/2019	06/05/2019
28/06/2019	06/07/2019
27/08/2019	05/09/2019
26/10/2019	05/11/2019
25/12/2019	04/01/2020
23/02/2020	05/03/2020
23/04/2020	05/05/2020
22/06/2020	05/07/2020
21/08/2020	04/09/2020
20/10/2020	04/11/2020
19/12/2020	04/01/2021
17/02/2021	05/03/2021
18/04/2021	05/05/2021
17/06/2021	05/07/2021
16/08/2021	04/09/2021
15/10/2021	04/11/2021
14/12/2021	04/01/2022
12/02/2022	05/03/2022
13/04/2022	05/05/2022
12/06/2022	05/07/2022
11/08/2022	04/09/2022
10/10/2022	04/11/2022
09/12/2022	04/01/2023
07/02/2023	05/03/2023
08/04/2023	05/05/2023
07/06/2023	05/07/2023
06/08/2023	04/09/2023
05/10/2023	04/11/2023
04/12/2023	04/01/2024
02/02/2024	05/03/2024

[L_T]

Thanks @mceleavey, this really helps! Appreciate all your help!

[mceleavey]