How to reduce "Masuk" automatically using $appends variable if I add data - laravel-8

Question

I'm fetching data from the warehouse table using the $appends variable, I want the "Masuk" column to be automatically reduced when I add the next data, but every time I add a data field, it's always fetched from the warehouse table, right? So how to reduce it? what to change in my code?
My views:
https://ibb.co/mT86hz7
My views
My serving model :
protected $visible = ['barang_keluar'];
protected $appends = ['barang_keluar'];
public function warehouse()
{
return $this->belongsTo(Warehouse::class, 'warehouse_id')->withDefault(['barang_keluar' => '0']);
}
public function setTotalAttribute()
{
return $this->attributes['total'] = $this->attributes['qty'] + $this->attributes['sisa_semalam'] + $this->attributes['sisa_today'] + $this->attributes['rusak'] + $this->attributes['double'];
}
// ==== ambil data barang keluar dari warehouse untuk dijadikan virtual field barang masuk di tabel serving ===
public function getBarangKeluarAttribute()
{
return $this->warehouse->barang_keluar + $this->attributes['sisa_semalam'] + $this->attributes['sisa_today'] - $this->attributes['qty'];
}
My warehouse model:
public function serving()
{
return $this->hasOne(Serving::class)->withDefault([
'nm_bahan' => '-',
'sisa_semalam' => '0',
'sisa_today' => '0',
'rusak' => '0',
'double' => '0',
'qty' => '0',
'total' => '0',
'ket' => '-']);
}
public function setSaldoAttribute()
{
return $this->attributes['saldo'] = $this->attributes['stok_awal'] + $this->attributes['barang_masuk'] - $this->attributes['barang_keluar'];
}