TDS on Prov march ending

If you are making provision for expenditure then you need to deduct and deposit TDS at applicable rates, failing which such expenditure will be disallowed.

Yes TDS have to be deducted on the provisions made. 

If you fails to deduct Tax at Source then as Section 201A following will be consequences

Non-deduction of TDS, either in whole or part

1% per month

From the date on which the tax was to be deducted to the actual date of deduction

Non-payment of TDS (after deduction)

1.5% per month

From the date of deduction to date of actual payment

If exp provision Rs.45000 of march ending Tds deduct 10 % on it but actual bill received lower amount in April of Rs.38000 how treat & if bill received higher amount of provision Rs.50000