I think you have the blockstun amounts wrong. AFAIK, the blockstuns for normal ground blocking are:
L1 = 8 frames
L2 = 10 frames
L3 = 12 frames
L4 = 15 frames
L5 = 17 frames
If I remember correctly, the IB modifiers are 0, -2, -3, -4 and -4 for ground IB, while normal hitstun and ground FD are +2 frames (+3 for crouching normal hits).
Below are listed the levels of Millia's moves as I remember them (there might be mistakes in there!):
L1: 5P, 5K, 2P, 2K, j.P, j.K
L2: j.214S/H, j.H
L3: S©, S(f), 6P, 2S, j.S, j.D, 236S/H, 214P, 214S, 236236S, j.236P
L4: 6K, 5D, 2H, 2D
L5: 5H, 6H, 2141236H
Without RC, Millia doesn't really have massive blockstun options. H disc hits, meaty late S disc hits and delayed pin hits can be used for similar effect though.