I stumbled upon this thread because I wanted to always reference the "cell to the left" but CRUCIALLY in a non-volatile way (no OFFSET, INDIRECT and similar disasters). Looking the web up and down, no answers. (This thread does not actually provide an answer either.) After some tinkering about I stumbled upon the most astonishing method, which I like to share with this community:
Suppose a starting value of 100 in E6. Suppose I enter a delta to this value in F5, say 5. We would then calculate the continuation value (105) in F6 = E6+F5. If you want to add another step, easy: just copy column F to column G and enter a new delta in G5.
This is what we do, periodically. Each column has a date and these dates MUST BE in chronological order (to help with MATCH etc). Every so often it happens that we forget to enter a step. Now suppose you want to insert a column between F and G (to catch up with your omission) and copy F into the new G (to repopulate the continuation formula). This is NOTHING SHORT of a total disaster. Try it - H6 will now say =F6+H5 and NOT (as we absolutely need it to) =G6+H5. (The new G6 will be correct.)
To make this work, we can obfuscate this banal calculation in the most astonishing manner F6=index($E6:F6;1;columns($E1:F1)-1)+F5. Copy right and you get G6=index($E6:G6;1;columns($E1:G1)-1)+G5.
This should never work, right? Circular reference, clearly! Try it out and be amazed. Excel seems to realize that although the INDEX range spans the cell we are recalculating, that cell itself is not addressed by the INDEX and thus DOES NOT create a circular reference.
So now I am home and dry. Insert a column between F and G and we get exactly what we need: The continuation value in the old H will refer back to the continuation value we inserted in the new G.
=INDIRECT("RC[1]",0)
– prograhammer