In Robert's Rules of Order Newly Revised (RONR), the effect of the motion, if adopted, is not to "postpone" the main motion, but rather to prevent action on it for the duration of the current session.
[3] It can also be used by opponents of a main motion to test whether they have the votes needed to defeat the main motion, without risking a direct vote.
[3] Using the rules in RONR, a main motion is improperly killed by tabling it.
[4] In this case, it would have been proper to make a motion to postpone indefinitely.
[4] The Standard Code of Parliamentary Procedure (TSC) does not have the motion to postpone indefinitely, and instead recommends use of this book's version of the motion to table (this version of "table" is different from that in RONR), which under these circumstances would require a two-thirds vote.