Free Shipping freeshipper is for when you have 0 weight and 0 weight means Free Shipping ... or ... when you have Always Free Shipping marked on a Product ...

Free Shipping Options freeoptions is for when you want a Free Shipping Option (slow boat to china) to show in addition to other shipping modules ...

Free Shipping set on the Modules ... Order Total ... Shipping ot_shipping for when amount >= XX.XX is for when you want no other shipping module showing and just have the shipping change to Free Shipping ...

You have to check on your rates as you are listing them with overlaps and I am not sure if you mean:

$1 to $10 is $6.99 and $10.01 is $7.50

or if you mean:

$1 to $9.99 is $6.99 and $10.00 is $7.50

If you do not use the Shipping ot_shipping your Zone Rate at $150 orders will show as $0.00 as there isn't a definition for this and you will always see the Free Shipping Options freeoptions depending on how you have that configured ...