-- get the temperature set point
local mbr_temp = luup.variable_get("urn:upnp-org:serviceId:TemperatureSetpoint1_Cool","CurrentSetpoint", 22)
-- add 5degrees to the set points of the thermostat
local plus_mbr_temp = mbr_temp + 5
-- set the thermostat to the higher temperature
luup.call_action("urn:upnp-org:serviceId:TemperatureSetpoint1_Cool","SetCurrentSetpoint",{NewCurrentSetpoint=tonumber(plus_mbr_temp) },22)
substitute your device number for 22 and use the correct deviceID by hovering over the variable in the advanced tab of your thermostat.
Sorry, forgot to tell you to set this in the Luup tab for the scene called “PlusFive” or something like that…