There's some exact words shenanigans here. Indeed may have reduced the number of tokens in the prompt by 80%, but they didn't reduce the cost by 80%: the prompt cost of inferring from a fine-tuned GPT-3.5-turbo ($3.00 / 1M tokens) is 6x the prompt cost of inferring from the base GPT-3.5-turbo ($0.50 / 1M tokens). If prompt tokens are cut to 20% of normal, then that implies the overall cost of the prompt tokens is 120% relative to their normal prompt: a cost increase! That's not even getting into the 4x cost of the completion tokens for a finetuned model.
Of course, Indeed likely has an enterprise contract reducing costs further.