mem widget doesnt shows real data like htop do

[dummys]

Hello,

Latest version of lain, I found an error when lain calculate the used memory. When I run htop I got 18.5GO/32GO used. When I use lain I got only 1569MO used.
Here is the full data of /proc/meminfo:

-> $ cat /proc/meminfo
MemTotal: 32554184 kB
MemFree: 2395704 kB
MemAvailable: 13061400 kB
Buffers: 360 kB
Cached: 28014172 kB
SwapCached: 1176 kB
Active: 14933608 kB
Inactive: 13932976 kB
Active(anon): 10062816 kB
Inactive(anon): 8150148 kB
Active(file): 4870792 kB
Inactive(file): 5782828 kB
Unevictable: 198972 kB
Mlocked: 80 kB
SwapTotal: 32505852 kB
SwapFree: 32474136 kB
Dirty: 204 kB
Writeback: 0 kB
AnonPages: 1051492 kB
Mapped: 17138932 kB
Shmem: 17360900 kB
KReclaimable: 598388 kB
Slab: 773420 kB
SReclaimable: 598388 kB
SUnreclaim: 175032 kB
KernelStack: 8160 kB
PageTables: 50364 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 48782944 kB
Committed_AS: 22089492 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 43208 kB
VmallocChunk: 0 kB
Percpu: 5024 kB
HardwareCorrupted: 0 kB
AnonHugePages: 14336 kB
ShmemHugePages: 0 kB
ShmemPmdMapped: 0 kB
FileHugePages: 0 kB
FilePmdMapped: 0 kB
CmaTotal: 0 kB
CmaFree: 0 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
Hugetlb: 0 kB
DirectMap4k: 430736 kB
DirectMap2M: 10776576 kB
DirectMap1G: 22020096 kB

Is the parameter MemAvailable ommited in the calculation ?