I don't think most people realize that 3.67% is, as a practical matter, well on its way to 90% weapons grade.
Enrichment isn't linear - it isn't like getting from natural to 3.67% is only about 3%-ish of the way to 90%-ish weapons grade. To the contrary, it is most of the way there for two reasons that work together:
First, each "pass" is multiplicative, e.g., 1.3x as enriched as the last. So one "pass" takes, for example, 1% to 1.3% or 50% to 65% (multiply by 1.3 in both cases)
Second, and more importantly, the amount of material needed to be processed is reduced on each pass. For example, if you start with 1000kg of natural uranium (which has about 7kg of U-235), you need to process all of it on the first pass, a little bit less on the second pass, and so forth. By the time you are to 50% enrichment, you only need to process about 14kg of uranium.
Together, these two effects mean that 3%-ish enrichment is well past halfway to 90% weapons grade - see chart.