Date Functions Without Standard Date Calendar

Hi Everyone,

I have been working through an issue for a couple of days now that I cannot figure out a solution too.

Essentially, I am trying to calculate MTD sales $ for LY but the data set that I am working with does not have a standard calendar assigned to it. The data has a "Process Week" with includes fiscal year and fiscal week in the following format ("202301"). Without specific dates assigned in the original data set I am having difficulty using the traditional time intelligence functions. Another issue I am having is that the calendar I need to be working off of starts in February instead of January due to our Fiscal Year. This also makes using the time intelligence functions difficult.

Any ideas on how I can calculate LY MTD $ without using time intelligence functions? I was thinking about using a "same period last year" formula but it is not working properly. Thanks!

I am going to include an example of the data set and the calendar table I have created for reference.