Can Give You a idea how to avoid creating multiple jobs for your requirement.
First you need to trigger your job at 7 Am and 8 pm using build schedule
Use Below script
Below script will check if you are running at morning or night , in weekdays or weekends and according to the timing it will either start/stop your environment
As said earlier this just an idea that will help you to approach , you need to tweak below code to meet your exact requirement
Note : Replace the echo section in start and stop part of goto with you code to start and stop environment
@echo off
echo Current Date and Time %date%-%time%
for /f %%a in ('date /t') do set "d=%%a"
set "t=%time:~0,2%"
if %t% GTR 12 goto Ni
if %t% LSS 12 goto Day
:Day
if %d% == Mon goto start
if %d% == Tue goto start
if %d% == Wed goto start
if %d% == Thu goto start
if %d% == Fri goto start
if %d% == Sat goto TBD
if %d% == Sun goto TBD
:Ni
if %d% == Mon goto stop
if %d% == Tue goto stop
if %d% == Wed goto stop
if %d% == Thu goto stop
if %d% == Fri goto stop
if %d% == Sat goto TBD
if %d% == Sun goto TBD
:start
echo start an application
goto last
:stop
echo stop an application
:last
echo last line