Do the accents sound right?

My first and most important question is: is it correct that after a sudden accent, the notes continue to sound in the dynamic range that was specified before the accent? Here is a simple video example: first there was a piano, then a crescendo to the sfz accent, and after that the volume drops to the initial piano. Is this correct? 00-57-53_1.ts On the one hand, the accents sfz, sff, fz, etc. act only on one note/chord, and on the other hand, there was a crescendo, but after that the sound became like a piano again.
And here's my second question. Do the accents in Musescore currently correspond to alphabetic characters in the way shown in the table below?