@asjdsm! I specifically told you not to use the engine oil. 20w50 is too thick, and is a colossal failure when it comes to front forks performance.
Your front forks operate under Hydraulics mechanics. That means, the oil inside will be worked just like its in the engine. A 20w50 will change its viscosity too often, and too quickly. Which means, your shock absorbers will be too hard in mornings, and too soft in extremely hot weather.
To maintain a balance, you should use Hydraulic Oil. (I don't recommend ATF, as a lot of websites and people here recommend. The reason is that you will have to change it often, every 5000kms or so, and thats 1) too inconvenient 2) enhances the spring wear in fork tubes; and 3) You have cheaper alternatives at your disposal).
Anyway, get any Power Steering Fluid (such as STP Power Steering oil). Costs a little below Rs.500 and works better than your normal engine oil.
You can refil your front forks at home, by yourself. Its not a difficult job. You can also utilize YouTube tutorials for some help. You don't even have to open the lower portion (fork legs), as that mechanic might have done, to change the seals.
Rear shock absorbers can also be redone the same way. Drill a hole, extract oil, refill new oil and you are done. Any mechanist can also do this job. However, I'd still recommend buying a new pair of rear shock absorbers.