There is a thread over in Link Building this morning from a guy watching his pages slide every time he points a keyword heavy anchor at them, three links in, and asking if exact and partial match are safe at all now. I did not want to call a cause over there off one post, and I still don't. But part of his question is really a buying question, so I will answer that part here.
Think about how you normally buy an anchor. You pick it once, on order day, going off whatever you believed about ratios that week. Then it is welded on. If you change your mind in March you are emailing a webmaster you have never met, or you are paying for the link twice.
On mine you can edit the anchor text and the target URL after it is live. No charge for it, no ticket. If a page gets jumpy and the anchor is your suspect, go dial it back to brand or generic yourself and leave the link exactly where it is. Want it keyword heavy again in six months? Fine, do that too. The paragraph around it gets rewritten to suit the new anchor, so you are not left with an obvious swap sitting in the middle of a sentence.
I would rather sell you that than something cheaper and welded shut. The one thing I genuinely cannot fix for you later is whether the host site sits in your lane, which is why I nag people about relevance and not about anchors.
Anonymised, so no names: US apparel store on this network, DR 30, 5,627 monthly traffic, 336 keywords in the top 3, and yes, we moved its anchors around more than once getting there.
If you already buy from me the edit panel is sitting in your dashboard, go play with it. Otherwise PM me with Give Me Back Control and I will send the discount over.