Universal Stop, system officially doesnt support stopping individual Zones so I technically dont care too much about its checksum  : 
4d454c001a01002dff5002ffffffffffffffffffffffff0f0118

What happens when sequence number rolls over :
4d454c00210100ffff300180000000000000000000000000010302010f010000f5
4d454c0021010000ff300180000000000000000000000000010302010f010001f4
4d454c0021010001ff300180000000000000000000000000010302010f010001fb


Tests using Sequence 00 (mostly) :

Repeat Increments for Melody 15 in Zone 8 at Volume 3 and bruteforced Checksums:
4d454c0021010000ff300180000000000000000000000000010301010f010001f3
4d454c0021010000ff300180000000000000000000000000010302010f010001f4
4d454c0021010000ff300180000000000000000000000000010303010f010001f5
4d454c0021010000ff300180000000000000000000000000010304010f010001f6
4d454c0021010000ff300180000000000000000000000000010305010f010001f7


Volume Increments for Melody 15 in Zone 8 with 3 Repetitions and bruteforced Checksum:
4d454c0021010000ff300180000000000000000000000000010103010f010001f3
4d454c0021010000ff300180000000000000000000000000010203010f010001f1
4d454c0021010000ff300180000000000000000000000000010303010f010001f5
4d454c0021010000ff300180000000000000000000000000010403010f010001f4
4d454c0021010000ff300180000000000000000000000000010503010f010001f7
4d454c0021010000ff300180000000000000000000000000010603010f010001f6
4d454c0021010000ff300180000000000000000000000000010703010f010001c9

Changign Zones from 8 to 8 and 16 :
4d454c0021010000ff300180800000000000000000000000010103010f01000173

Melody 1 in Zone 8 and 16 only once at Volume one Sequence Number 2:
4d454c0021010002ff30018080000000000000000000000001010101010100014d

Melody 1 in Zone 1 once at Volume one Sequence Number 3 :
4d454c0021010003ff300101000000000000000000000000010101010101000149

Meoldy 1 in Zone 8 and 16 only once at Volume one Sequencence Number 0:
4d454c0021010000ff300180800000000000000000000000010101010101000143

Melody 1 in Zone 1 once at Volume one Sequencey Number 0 Repetition Increments:
4d454c0021010000ff300101000000000000000000000000010101010101000144
4d454c0021010000ff300101000000000000000000000000010102010101000143
4d454c0021010000ff300101000000000000000000000000010102010101000142

Melody 1 in Zone 1 once at Volume 2 Sequence Number 0 Volume increments :
4d454c0021010000ff300101000000000000000000000000010101010101000144
4d454c0021010000ff300101000000000000000000000000010201010101000145