You're probably more familiar with California law, but as far as I know there is no California policy or law regarding patient ratios with pressors, the ratio laws only apply to patient location, which just requires that a an ICU patient not exceed a 1:2 ratio, and BON policy/rules never get that specific.
ACCN does have guidelines for 1:1 care, although ACCN guidelines are not enforceable. Their guidelines were written in 2000 and are already way out of date.
Today they are only useful as an interesting look at how things have changed in the last 10 years. The parameters they give for making a patient 1:1 are now the parameters required to be in ICU in general, much less 1:1, many of the patients described as requiring 1:1 care in 2000 are now 4:1, some of these patients may even be on a 1:6 ratio floor. This absorption of higher acuity in stepdowns and lower acuity floors is why the supposed nursing shortage never materialized.
I could see not wanting to take two patients were being actively titrated on levo if we still did only manual BP's, but with automatic NBP's, and even better an art line, there's no reason why a nurse can't titrate two patients at the same time.