Its a great way to get those mid sized orders, at a competitive price.
You need to evaluate the local competition, will you have the market to yourself or is it already flooded? If there is little competition then you could be unbeatable on price.
Screen printing is a wet process - can you make it sit alongside your existing dry operation? Dtg printers and pressure washers don't always mix.
When printing constantly its all fairly straightforward. If you have to dig the equipment out twice a month then it can be tiresome and time consuming.
Once each job is set up its an incredibly fast method of production and you will be able to tackle the larger jobs easily. Just think of every stroke as another dollar.
When all is said and done screen print is still the best combination of quality, durability, speed and price out there. Dtg is still developing and is many years away from bettering screen print on any of those terms. It probably will eventually, but as it stands a good Dtg printer capable of 15 12" x 16" images an hour costs about the same as an auto that can print 60 dozen shirts an hour.
Other decoration methods all have their plus points, but they are mainly lower volume,higher price promotional solutions. If you can make screening fit in you could be expanding your potential customer base.