calculation

( 100% of employee compensation (< $22500)  + 25% of employee compensation ) < $73500

Let's say your annual Self-employment income is $100,000

self-employee contribution =  $22500  (max)

self-employer contribution = $25000  (25% of 100K)  

So 47500 is exempted from taxes,  and $52500 are subjected to income tax and SE-employment tax (15.3%) 

So you pay $8032 more in tax to delay the tax for $47500.