First time getting hazmat, and I have to choose between H and X. Is it true that H is the standard hazmat and X is for tanker hazmat?

I already have a tanker endorsement, but the job I'm doing this for is dry van. Should I apply for the H or the X? I wouldn't mind having the the "extra" endorsement, but is the process more complicated?

(T) DOUBLE or TRIPLE TRAILERS. For tractors pulling two or three trailers.
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(P) PASSENGER. For vehicles which are designed to carry 16 or more people (including the driver);
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(S) SCHOOL BUS. Any vehicle transporting children to or from school and home regularly for compensation.
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(N) TANK VEHICLES. For vehicles designed to haul liquids or liquefied gases in bulk in permanently mounted tanks or portable tanks rated at 1,000 gallons or more.
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(H) HAZARDOUS MATERIALS. To carry hazardous materials in amounts requiring placards.
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(X) Endorsement code designating a Tank (T) vehicle that carries Hazardous Materials (H).

your T endorsement will become an X when you get your haz mat endorsement

Thanks.