OP here.

A couple of small known issues I haven't fixed up yet:

  * I'm not correctly taking into account the number of coupon payments in the current year and final year for each bond, just assuming it's 4 like every other year.
  * Prices are updated manually, I've got some code that scrapes the ASX to get new prices, just needs to be hooked up.

I'd be particularly interested in feedback on usability, or ease of understanding from non-finance experts. I've added a bunch of long-winded copy that tries to explain what this is for, but I'm not sure it gets the point across clearly.

Once this is a bit more polished, I'll publish a version that does the same calculations with US TIPS instead of Australian eTIBs.

Thanks!