Pension contribution methods
Salary sacrifice, net pay and relief at source are not the same, even when the percentage looks identical.
Where the relief goes
With relief at source, basic-rate relief is added to the pension. Any further relief reduces your tax. It should not be added to the pot a second time.
A defined contribution pot is part of net worth. A defined benefit pension is a future income, not a second copy of the same money. The State Pension is also an income assumption.