It is not a rumor. it is stated in your OAT handbook on page 40 i believe. The calculator was implemented May 2010
A thread search will show you that there are few who found the calculator useful or used it for only 1 or 2 questions. Be aware that you cannot use the 10-key pad to punch in numbers, but rather, you must click each digit with your mouse.
Some SDN members also reported that the calculator lagged on their computer and did more harm than good. My calculator did not have lag, but most of my questions had algebra that was much quicker to do by hand rather than by calculator. Very few were complicated enough where i felt that the calculator would save me time.
as a fun anecdote, i go on very long drive every weekend. To help strengthen my mental math i often added up the digits on license plates of other cars in my head as fast as i could. it had been a while and i felt that helped strengthen my mental math speed. every bit helps
