It sounds like we more or less mean the same thing. A miniblock full of zeroes will take no space at all (just the bitwidth of zero in one byte in the block)
example: 
let's say we encode: 1, 2, 4, 7 in 4 miniblocks of 8 values (32 values total).
we will need to pad the block with 29 zeroes (4 values => 3 deltas).
first value: 1
deltas: 1, 2, 3
data:
header: 32 (# values in a block), 4 (# of miniblocks in a block), 4 (total # of values), 1 (first value)
first (and last) block: 1(min delta) , 1 (bitwidth 1st miniblock), 0, (bitwidth 2nd miniblock), 0 (bitwidth 3rd miniblock), 0 (bitwidth 4th miniblock), bitpacked(2 (width), {0,1, 2, 0, .... } ) (1st miniblock), bitpacked(0 (width), {0, 0, 0, 0, .... } ) (2nd miniblock), bitpacked(0 (width), {0, 0, 0, 0, .... } ) (3rd miniblock), bitpacked(0 (width), {0, 0, 0, 0, .... } ) (4rth miniblock)
with bitpacked(bitwidth, values) the bitpacking function and bitpacked(0, values) always returning an empty byte array.