something like this maybe, but i didnt try it to see if it worked
#include <amxmodx>
#define PLUGIN "CVAR Query Example"
#define VERSION "1.0"
#define AUTHOR "diamond-optic"
public plugin_init()
{
register_plugin(PLUGIN, VERSION, AUTHOR)
register_clcmd("query_interp", "cvar_query", 0, "- should return your ex_interp value")
}
public cvar_query(id)
{
if(!is_user_bot(id) && is_user_connected(id))
query_client_cvar(id ,"ex_interp","cvar_result")
}
public cvar_result(id,const cvar[],const value[])
{
new Float:value_float = str_to_float(value)
client_print(0,print_chat,"value: %f",value_float)
}