Is this heloc straight?

[JayCinta Henry]

I am new to helocs. Taking out a heloc on my primary, no mortgage note. Comps in my neighbor peg house value at $348K.  If a bank does 80% but is availing a $220k line. Am I on the loss for something here?  Why won't they offer a $278K or close? Why are they putting my primary value at $275K (80%=$220K.)  Is this is standard bank practice or is the bank trying to protect themselves/hedge against future home value softening?  Am I missing something, is this putting a risk on the house?  Should consider this heloc with such a gap or is that enough for a hard pass? 

P/S

I reached out to them about this but haven't heard back. WIll follow up on Monday.