I've just noticed some errors in the first of the two KB articles., in the section headed "What are the different tariffs?"
In the goodybag column it states "To check how many minutes and texts you have got left dial *100#7 (more info)" *100*7# does minutes, *100*5# does texts (NB these codes are only relevant for £5 and £7.50 goodybags)
Under that table it states "You can only buy one goodybag each month, so you need to wait for your current 'bag' to expire to be able to buy a new one." No mention of 'start early' (although this is mentioned later in the article)
I do not work for giffgaff, so cannot check anything on your account. This is a public community - please do not post any personal info.