wpa_supplicant roaming to better signal

Question

I have a router (with access pont) and an access point connected using an ethernet cable. Both access points have the same SSID, password, encryption,...

I tried to use the wpa_supplicant package. First of all I created a file /etc/wpa_supplicant/roam.conf:

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
    ssid="work"
    scan_ssid=1
    key_mgmt=WPA-PSK
    psk="password_here in plain text"
    id_str="network_work"
    priority=3
    bgscan="simple:5:-70:200"
}

And I modified the file /etc/network/interfaces like this:

auto lo wlan0
iface lo inet loopback

iface wlan0 inet manual
   wpa-driver wext
   wpa-roam /etc/wpa_supplicant/roam.conf

iface network_work inet static
   address 192.168.1.67
   netmask 255.255.255.0
   network 192.168.1.0
   broadcast 192.168.1.255
   gateway 192.168.1.1

iface default inet dhcp

I usually connect to AccessPoint1 and I move around and when I loose the signal, it changes to the other AP but I have around a minute gap between this change, and I lose my network connection for this minute.

What I was trying to do is, in case the signal of the AP1 gets to -70dB to change to the other AP, in case the other has >-70dB. Is this possible?

I did a test: sudo watch -n1 "iw wlan0 scan | grep 'BSS\|signal'" and when the signal of the AP1 was at -90dB it keept connected to that AP. And it should have changed to AP2 which had only -80dB

To be clear: it roams between both AP if the signal to one of them is lost, otherwise it stays at the AP it connected first. I'd like to connect to the strongest signal once a threshold is passed (-70dB). Or at least change AP when the signal with one of them is really low. If I connect with another laptop, both access points appear as one in the network manager

Thanks!