CA-4 and Visa Renewal

Hello, I didn´t see this posted anywhere so thought I would ask:

Does anyone have any recent experience extending their 90 Day Central American Visa (the CA4 btwn Guat, El Salvador, Honduras and Nic)? We are in Guatemala and will definitely need more time as we head south, and I read a bad experience elsewhere about renewing in Honduras where we think we will be when our first 90 are up.

Is it possible to renew in Honduras, and if so, is it only in Tegucigalpa? Can you get the full 90?

Otherwise, I know it´s possible to extend in Guatemala City or in El Salvador, but will they extend it from the day you go to the immigration office or from the end of your 1st 90 days? The latter would obviously be better for us because then you´re not effectively losing days.

Any info/help/experiences or advice is appreciated. Thanks.

If you renew in Guatemala City you get 90 days from the date of your renewal. I don't know about the other three countries.