It seems to make sense to me if you know that a Masters can take 1 year .
http://tsrmatters.com/wp-content/uploads/2016/06/SFE_PGL_main-guide_1617_v1.6_D_A.pdf
"How much can I get?
You can get up to £10,000 for your whole course.
If your course is longer than one year you can get up to £5,000 in the first year and the rest in your second year.
If you’re studying part time for three or four years you’ll get all your
Postgraduate Loan payments in the first two years of your course."
As to the £10000 being a maximum the document says "You’ll be asked how much Postgraduate Loan you want, up to the maximum of £10,000. If your course is longer than one year, you’ll be asked how much you
want in your first year. You can get up to £5,000 in the first year of your course and you’ll get the rest in your second year."
So you can ask for what you need up to the maximum. There is an application process. However I don't whether the full requested amount is approved automatically (provided you meet the criteria) or whether there is some means testing