Confusion regarding the duration of money held in bank acct!

Good morning.
I was going through the T4 guidance and got confused with the following:
"
164 The money you show us must be for your use for studying and living in the UK. The full amount of this money – which should be held in the manner specified in this guidance – must continue to be available to you after your application is made, except for any money you have to pay for course fees and living costs.
For example, you should retain the full amount of money you have shown us in your bank account, minus the balance you have paid for your course fees."

To me, it's contradictory with the following statement :

"182.You must show that you have held the required money for a consecutive 28 day period (finishing on the date of the closing balance) ending no more than 31 days before your application."

Can someone clarify me the duration please? Thank you in advance.

It is not a contradiction, it is explaining (or rather just repeating) two separate requirements of Appendix C, paragraph 1A, which specifies the rules about maintenance.

(c) If the applicant is applying as a Tier 4 Migrant, the applicant must have had the funds
[...] for a consecutive 28-day period of time;

This is proved by paper evidence: your bank statements, bank letter, etc. showing you have held the relevant amount in your name for 28 days.

(ca) If the applicant is applying for entry clearance or leave to remain as a Tier 4 Migrant,
he must confirm that the funds referred to in (a) above are:

(i) available in the manner specified in paragraph 13 below for his use in studying
and living in the UK; and

(ii) that the funds will remain available in the manner specified in paragraph 13
below unless used to pay for course fees and living costs;

These are proved by you checking the relevant box on the application. If the entry clearance officer or caseworker suspects that an applicant has used deception, and that the money they have shown is not for paying their fees and living costs, they can check. Someone who, for example, showed evidence of money they have just borrowed for the application would be refused under that paragraph and for having used deception.

Thank you so much for your reply Sah.