How to calculate movements between columns?

[mylesco]

I have a dataset where an amount can move forward any number of columns, backwards any number of columns, can be removed or added.

I want to find the balance only, of those that have moved forwards and backwards, disregarding those who have been added or removed. For example in row f below that although a 100 balance was added to column 4, I only want the balance of the 300 that moved from column 3 to column 2.

Current Week:

ID	1	2	3	4
a	100	0	0	0
b	0	500	0	0
c	300	100	0	0
d	1200	200	100	0
e	0	0	0	100
f	200	300	0	100

Last Week:

ID	1	2	3	4
a	0	0	0	100
b	500	0	0	0
c	300	0	100	0
d	1200	0	100	200
e	100	0	0	0
f	200	0	300	0

For some reason the second table just doesn't want to work so here is a picture:

List of Movements are below:​

a: Pulled forward from 4 -> 1: 100
b: Pushed from 1 -> 2: 500
c: Pulled: 100
d: Pulled: 200
e: Pushed: 100
f: Pulled: 300

Output​

This is what I would expect the output to look like in the end:
Pulled: 700
Pushed: 600




Thank you in advance and anymore question let me know!