Hi Rha,
*** A NFR is not necessarily always related to a toe release as the weight is received onto the new supporting leg. ***
Rha. (1) When a side step follows a no foot rise (NFR), the supporting foot will be flat and when full weight is taken on to step 2, the heel of step 1 will be released from the floor. eg 1-3 of Natural Turn in the Waltz as lady.
(2) When a backward step follows a NFR, the toe of the supporting foot is released from the floor so that when step 2 is taken pressure is felt in the heel of the front foot. A body rise will be felt between the heel of the front foot and the ball of the back foot. eg Feather Step as lady in the Slow Foxtrot.
(3) When NFR follows a side step, the heel of the side step will lower as the next step is taken to end Up NFR eg steps 2 and 3 of a Feather Finish, as lady.
*** I don't dance that step with footrise either (Step 4 Reverse Turn, as man) but I also don't have a toe release like the NFR in the Reverse Wave. So I dance it with NFR but a heel release like the backhalf of many other figures. ***
Let's just think about that one! You are dancing step 4 of the Reverse Wave, as man. You've extended the right foot back on to the toe then lowered in to the heel and the body weight rolls through the right foot into the heel when the left foot is taken back on to the toe (step 5). Now with the weight in the right heel you shift it forward to the right toe so that you can release the heel of the right foot before you take the right foot back (step 6). Rha, have you ever considered you are at fault?