Correct. this means that you have only 30 amps of 240 VAC power.
I have a 70 amp sub panel, I will check out the wire size going to the outlet, if they will handle 40 amps I might upgrade the breakers to 40 if I have trouble using small rod on the 30 amps. Pretty sure the wire size is 10guage with a 12 foot run to the outlet.
10 gage is good for 30 amps.