I suspect you are right. For context, I was assuming a 20x w/ OpenAI or Anthropic subscription as the comparison (or both). dsf 4.1 was going to run me about 2-3 times the cost of either of those for the same amount of work. Obviously you can optimize differently, but that's true of subscriptions too. I was using pi and had it evaluate it's ideal context compaction point based on usage and API rates. Keep in mind though I was using a ZDR provider, so slightly higher costs. If I want them to train on my code, I could shave a few $ off.
That's not even taking into consideration all of the resets you get from the frontier subs. Which lately seems to at least double usage (more like 5x recently with OpenAI if you count the credit grants). But OpenAI is tweaking it's pricing, so it's always a moving target... which is kind of annoying until you learn to just ignore it.