No, in commercial real estate when you say $30/sqft it's already annualized. That's 30 / 12 = $2.5/sqft/mo. Also you're looking at listings for 10k or less, at 500k space it's a very very very different game.
San Francisco (highest I could find) - is $34.32/sq foot/annually. So, applying your rule, one would pay $34/sq/foot/month. So - a typical 1500 square foot commercial office would be $51,000/month? Seems high even for San Francisco. If we instead divided by 12, $2.86/sf/month, then $4300/month for 1500 square feet seems within the realm of reason.
How certain are you that these rates are already converted into monthly values?
I found one monthly rate for Kentucky,
2,500 - 8,432 SF, $1,016 - 5,578 (Monthly).
That would be $0.40/month - $0.66/month, or, multiplied by 12, $4.80-$8/year. Right within the expected range.
Great work. Do note that this is an NNN lease, though, which means the tenant pays property tax and operating expenses. For a new warehouse like this one, this site says these fees average 58% of the base rent: http://fgpcl.com/what-to-expect-with-triple-net
