Hello @HaxMammond, thank you for contacting us. Hope you are doing well! To start, we currently require a minimum of 25 cards to be submitted under the bulk grading tier to qualify. If you have 10 cards to submit, unfortunately, they would not qualify for bulk since it does not meet the minimum quantity requirement.
You may mix tiers on the same order, however, mixed tiers will not qualify under bulk itself since you must have a minimum of 25 cards under the actual bulk grading tier. What I mean by this, is for example you have 20 cards under Economy and 5 under Express, that does not qualify them for bulk since bulk is its own grading tier. Hopefully, this makes sense! If instead you are asking if you can send them in the same box, then yes, you may submit cards in different grading tiers in the same package.
Please let us know if you have any additional questions. Thank you!