I’m pretty sure column A doesn’t do anything. The only columns that Tiller feeds data into are certain columns with specific names in the first row.
More info about those names and columns here:
Tiller sheets are designed to work no matter where you have these columns. We do a lookup in the hidden parts of some sheets to find which columns these standard names are in.
Most formula cell references will automatically adjust when you move the columns. However, if you write a QUERY() function and use Column letter inside the SELECT statement, those letters won’t be updated when columns move. We solve this by using a reference to the column name lookup results mentioned above.
But if you write your own QUERYs with direct column references and then move some columns, your original formula may not work.