Toro 30" came out last year. People did not like it's cut quality.
You do not bid a lawn based on the size mower you have. You bid it on your costs and profit that you need to make to stay in business.
Example numbers are used for ease:
Your need to charge $60 to stay in business.
1 acre lawn goes for $60 in your market area.
It takes a your competitor A with a 48" mower 1 hour to mow the lawn.
Does competitor B with a 60" mower that can do the lawn in a half hour charge $30?
No. A 1 acre lawn goes for $60. There is no reason because B can get it done faster he must charge less. His 60" mower cost double the money to buy and uses more gas.
You have a 21" push and it will take you 2 hours to mow the lawn. Does that mean you charge $120?
No. Because to ask that price double of what the market will bear you will not get any business. You charge $60 and save your money to buy a bigger mower.