Maximum 16 characters vs At most 6 characters

Some examples from the web:

• EIC code, 16 character alphanumeric code.
• Build and save 3 custom sets of 16 characters for extra practice - an MFJ exclusive.
• I'm up to 16 characters on the encryption code, but then... I run out of time.
• Finland has applied the allowance only to a limited extent and restricted the import of beer to a maximum 16 litres per person.
• access is only permitted in a group (maximum 16 persons) led by a certified tour guide or instructor affiliated to either the NKB (Dutch Canoe Association) or the TKBN (Dutch Tourist Canoeing Association),
• access is only permitted in a group (maximum 16 persons) led by a certified tour guide or instructor affiliated to either the NKB (Dutch Canoe Association) or the TKBN (Dutch Tourist Canoeing Association), setting foot on tidal plains is prohibited.

Some examples from the web:

• Field 2 has to be freely filled with a 6-character alphanumeric code.
• Field 2 has to be freely filled with a 6 character alphanumeric code.
• Your password must be at least 6 characters long, cannot contain your username, and must contain at least one letter and number.
• National administrations that want to have the office reference number of the competent authorities included in the MRN could use up to the first 6 characters to insert the national number of the office.
• If a scrolling display is used (either horizontal or vertical), each complete word shall be displayed for a minimum of 2 seconds and the horizontal scrolling speed shall not exceed an average of 6 characters per second.
• National administrations that want to have the office reference number of the competent authorities included in the MRN, could use up to the first 6 characters to insert the national number of the office.
• an... 6 up to 6 alphanumeric characters
• Maximum 20 characters 6 bit ASCII, = not available = default
• UN country code using 2*6-Bit ASCII characters according to ERI specification
• 7 × 6 bit ASCII characters, ' ' = not available = default [8]
• Maximum 20 characters using 6-bit ASCII; = not available. [13]
• Nothing happens at most board meetings.
• Freon is available at most computer stores.
• European subsidies should at most play a supplementary role.
• Pension reforms have been partial at most.
• It was reported to me at lunchtime by a representative of the duty-free lobby that there were at the most 6, 000 people there.
• The Agency may comprise at most 40 to 50 people and cost at most between EUR 6 and 7 million per annum, covered by Community grants.
• I am convinced that if this committee has no indicators at its disposal it will remain at most a paper tiger and at most capable of producing reams of paper.
• At most two grapes per stalk may remain.
• The husk contains at most three fruit.