Cannot buy mercs when within 5 levels below them

Expected: I, a level 13 adventurer, should be able to buy a merc within 5 levels of me. General 'help buy' states this: "You can only buy an item of your level plus five or lower, not including wands, talismans or scrolls (which can only be purchased if you are at or above their level). An exception is that anyone can buy an item (but not a pet/mercenary) of level 1-10, even if their own level is lower. " Actual: I went to buy a swarthy mercenary in Hamsah, which is level 15 NPC. I got the message that I cannot control this mercenary yet. Steps to Reproduce: 1) Try to buy a merc that is within +5 levels of you. Possible explanation: maybe the help file is unclear and this works as intended. In that case, please update the help file to say "You can only buy an item of your level plus five or lower, not including wands, talismans, scrolls or pets/mercenaries [snip]".