Stop using Dektol and switch to Ethol LPD developer. It's available in liquid or powder form(powder is more economical). You can adjust the tone of the print from cool to warm with the dilution of the developer. Stock to 1+1 will give a deep black, while more dilute will give warmer tone, without having to adjust developing times.
My favorite paper developer. I like the flexability.
Moma don't take my Kodachrome away!
Oops, Kodak just did!
Second (third) Rick's suggestion. I use LPD, 1:2 from stock, 2 minutes with Ilford MG (although glossy) and get neutral results, with Ilford MGWT (warm tone) slightly browner. Both deepen with selenium toner, but the change is less obvious with MGIV.
Honestly, I find that Multigrade has this tendency even with a different developer. I have standardized on Freestyle's Eco-Pro liquid developer and MG looks pretty good in it, but I always selenium tone it. It looks good without the toning, but the blacks really deepen with toning.