Use MAP with ACL Runtime API not with use_backend

Configuration Samples
1

Hello I want to setup ACL with using the Maps, but I’m not sure if we can setup similar settings.

This is the current config.

frontend master
       use_backend slow if {  be_conn(master_backend) gt 100 }
       use_backend master_backend

I want to rewrite it with ACL and Maps

frontend master
       acl more_than_100 be_conn(master_backend) gt 100

       use_backend slow if more_than_100
       use_backend master_backend

default.map

more_than_100 100

frontend master
       acl more_than_100 be_conn(master_backend) gt %[int(more_than_100),map(/etc/haproxy/maps/default.map)]

       use_backend slow if more_than_100
       use_backend master_backend

Questions:
#1. Is it even possible to use maps as ACL for anywhere in config?
#2. Not sure how can I fix the config here.

Reason: Why I want to do this is, I want to update this ACL condition values with HAPROXY Runtime API but rather than update with ACL I want to do it with Maps. I want to update Maps value on runtime basis so that will update the ACL condition values too.