Well, I would not put it quite that way....

Determinate tomatoes put on their vegetative growth. Then when it is time,they set flowers, and set fruit.  The fruit is set not at once, but in a small(er) window. 

Indeterminate tomatoes start their vegetative growth.  Then when it is time they start to flower,and set fruit. Meanwhile, they continue with vegetative growth, and continue to flower and set fruit.  A much longer fruiting season, but not all season long.

Soybeans do a similar thing.  Soybean maturity 0-IV will start with vegetative growth. When it is time, they start to flower and set pods. Meanwhile, they continue with vegetative growth, and continue to flower and set more pods.

Soybean maturity V and up will start and complete their vegetative growth before they start to flower, and then set pods.  

edit: how long have you been growing tomatoes?