Personalisation policies, which have near-universal support from the Government, councils and care providers, are meant to give elderly and disabled people and their carers a choice of the services they receive, and help keep them in their own homes.
But care providers have long warned there is a basic incompatibility between this choice and procurement rules councils follow when commissioning services.
When they are given budgets for self-directed support, many families have been dismayed to find they cannot use them to buy the care they want because the charity or company providing it is not on an approved list.
Sometimes an older person has been getting care at home or other help for years and must change providers against their wishes.
South Ayrshire Council has just said a popular specialist charity for dementia sufferers did not make its list of providers in part because it does not cater for children.
Annie Gunner Logan, director of Community Care Providers Scotland (CCPS), said: "There is a fundamental incompatibility between a procurement process which puts the public body in charge of choice and self-directed support which is supposed to put individuals in control."
A working group bringing CCPS together with Cosla, the Scottish Government and other stakeholders is currently looking at the problem. Meanwhile the recently passed Procurement Act makes it clear health and social services can be exempt from procurement rules. It will also lead to specific guidance for councils.
However, several councils continue to tender for care services. Eileen Alexander from Ayr has cared for her mother, who has dementia, for three years and has had home day-care from specialist charity South Ayrshire Dementia Support Association (SADSA).
The local council recently carried out a tendering exercise which saw services transferred to private company Belhaven Care. Families cannot choose services from SADSA, which missed out in the tendering exercise.
Ms Alexander says the agenda is cost-cutting, not providing services people want. "This is supposed to be person-centred, but we have a perfect service at the moment. Nobody asked us if we were happy. There is a lack of understanding about what dementia sufferers and their families really need."
The Herald's NHS Time for Action campaign is calling for a review of capacity within the NHS and social care and a plan for it to adjust to meet the needs of the growing elderly population.
Les Anderson, chair of South Ayrshire Seniors Forum, said it was important people could choose services. "An increasing area of work for us is advice and guidance on care services which work badly or are not appropriate."
The Scottish Government says implementing self-directed support is a matter for local councils, and a spokeswoman said councils should not let tendering processes get in the way.
"The Self-directed Support Act makes clear that local authorities, through their approach to commissioning, should ensure that services are provided as flexibly as possible," she said.
A Cosla spokesman said the organisation was working with its partners to ensure "that the implementation of self-directed support provides the maximum of choice and control to people with support needs, whilst at the same time ensuring that councils are able to meet their statutory obligations".
Kenny Leinster, head of community care at South Ayrshire Council, said SADSA was unsuccessful in a recent procurement process focused on quality and price for home care services, but service users would continue to get excellent care.
He added: "If someone asks to receive their service in a different way we would be happy to discuss the options available to them."