Attack Bar Fill Up Question

Why does Moore always cut in when Dark Megumi S3 on him w/ full 40% pushback?
My uneducated logic is that fillup = 100%, so 100% - 40% = 60% but his attack bar visually doesn't even decrease so I assume its because he gained 100% + whatever he started with initially (80%). So in my case, even after the decrease he is still at 140% attack bar. Is that the case?