You shouldn't have to print 2 passes 16 pass 1440, that's ridiculous.
Are the nozzles firing 100%?
I've been printing out of Rasterlink today and some of the profiles were laying down too much ink for me. I've also just printed full Pantone solid to process CMYK swatches using different profiles and settings and can say that they hit reds really well.
That being said, my inks are slightly different to yours. I'm using Mimaki eco-hs1 inks, which is kinda between their eco and ss21.
Maybe check that your file is coming in properly.
Send 1 strip of pantone CMYK colors from your
sign program and compare the CMYK values in Rasterlink by hovering the mouse over the patches in "color edit/color replacement".
Make sure they're still CMYK and the numbers match the original formulae.
Print a swatch with the CMYK input profile turned off and compare it to one using WideMimaki CMYK. My preference is to use WideMimakiCMYK for better Pantone matching.
Have a look here, there's a good selection of Eco profiles
http://dgsmimaki.com.au/pages/downloads/Raster/RLP Profiles.html