Is there a particular reason why you stopped offering 1 month premium codes? Some buyers may be interested in trying the Lynda.com service before buying it, and the 30 day premium accounts were a good way to do that. Now the only option is to risk paying for a year of service that you are not sure is suitable for you.
Yes sir, the reason is LYNDA now only allows 12-months premium to be given as gift. It has stopped 1-month premium service but only as gift.
P.S. Also I am giving the full warranty on all my accounts just to cover the risk involved as loss of account.