You are incorrect - our patient's systolic murmur at the upper left sternal edge is best described as early peaking and the diastolic murmur as decrescendo.
Your choice: Systolic plateau shaped + mid diastolic
This is a graphic example of a systolic plateau-shaped murmur and a mid diastolic murmur.
Note that the systolic murmur is high frequency and the diastolic murmur is low frequency.