Again I do not read it that way.
225.30 is titled number of supplies not number of feeders or branch circuits
it further states from the load side of the service disconnecting means their can only be one feeder or branch circuit supplying a building or structure that is supplied by a feeder or branch circuit
That would be a additional building s from a single service disconnecting means
Not saying you can't or shouldn't read it that way. I'm only playing the role of devil's advocate for our discussion...
Yes, 225.30 is titled Number of Supplies, but you also have to take into account the context of the Article title "Outside Branch Circuits and Feeders", scope as described in 225.1, plus the Part II title "Buildings or Other Structures Supplied by a Feeder(s) or Branch Circuit(s)".
Additionally, the general consensus regarding Code implementation is permissive. That is, unless specifically prohibited the objective is permitted. Neither Article 225 or Article 230 specifically prohibit a building or structure from being supplied by both a service and a feeder or branch circuit.
Also, you're also assuming the fact both originate from the same source has bearing on the matter. Consider 225.30(D), which states "Additional feeders or branch circuits shall be permitted for different voltages, frequencies, or phases or for different uses, such as
control of outside lighting from multiple locations." It only uses the underlined as an example. Does this specifically exclude a desire to power a load or loads through a different meter? No.